From 2d3382a8b41b6649e4062d2cc41f9c94d8487eca Mon Sep 17 00:00:00 2001
From: Garfield Tan <xutan@google.com>
Date: Wed, 4 Aug 2021 14:17:31 -0700
Subject: [PATCH 1/2] Render window decoration in WM shell

There are still several things missing in this CL:

1. Still need to wire up freeform resizing. This is done in a separate
   CL.
2. Check if a11y works as intended.
3. Wire up fullscreen and window decorations for freeform displays.
4. Immersive mode work.

Bug: 165794880
Bug: 165794636
Test: Caption shows up.
Change-Id: I7c0e1d55d6c9d03332a58d31ade88aef06a84048
---
 .../res/color/decor_button_dark_color.xml     |  21 ++
 .../res/color/decor_button_light_color.xml    |  21 ++
 .../res/color/decor_caption_title_color.xml   |  23 ++
 .../res/drawable/decor_caption_title.xml      |  22 ++
 .../res/drawable/decor_close_button_dark.xml  |  32 +++
 .../drawable/decor_maximize_button_dark.xml   |  36 +++
 .../res/layout/caption_window_decoration.xml  |  45 +++
 libs/WindowManager/Shell/res/values/attrs.xml |   4 +
 .../Shell/res/values/strings.xml              |   8 +
 .../com/android/wm/shell/ShellInitImpl.java   |   4 +-
 .../wm/shell/dagger/WMShellBaseModule.java    |   8 +-
 .../wm/shell/dagger/WMShellModule.java        |  25 +-
 .../shell/freeform/FreeformTaskListener.java  |  53 ++--
 .../CaptionWindowDecorViewModel.java          | 136 +++++++++
 .../windowdecor/CaptionWindowDecoration.java  | 143 ++++++++++
 .../windowdecor/TaskFocusStateConsumer.java   |  21 ++
 .../windowdecor/WindowDecorLinearLayout.java  |  72 +++++
 .../windowdecor/WindowDecorViewModel.java     |  49 ++++
 .../shell/windowdecor/WindowDecoration.java   | 265 ++++++++++++++++++
 .../core/java/com/android/server/wm/Task.java |  42 ---
 20 files changed, 954 insertions(+), 76 deletions(-)
 create mode 100644 libs/WindowManager/Shell/res/color/decor_button_dark_color.xml
 create mode 100644 libs/WindowManager/Shell/res/color/decor_button_light_color.xml
 create mode 100644 libs/WindowManager/Shell/res/color/decor_caption_title_color.xml
 create mode 100644 libs/WindowManager/Shell/res/drawable/decor_caption_title.xml
 create mode 100644 libs/WindowManager/Shell/res/drawable/decor_close_button_dark.xml
 create mode 100644 libs/WindowManager/Shell/res/drawable/decor_maximize_button_dark.xml
 create mode 100644 libs/WindowManager/Shell/res/layout/caption_window_decoration.xml
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskFocusStateConsumer.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorLinearLayout.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java

diff --git a/libs/WindowManager/Shell/res/color/decor_button_dark_color.xml b/libs/WindowManager/Shell/res/color/decor_button_dark_color.xml
new file mode 100644
index 0000000000000..bf325bd84c001
--- /dev/null
+++ b/libs/WindowManager/Shell/res/color/decor_button_dark_color.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+          xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item app:state_task_focused="true" android:color="#FF000000" />
+    <item android:color="#33000000" />
+</selector>
diff --git a/libs/WindowManager/Shell/res/color/decor_button_light_color.xml b/libs/WindowManager/Shell/res/color/decor_button_light_color.xml
new file mode 100644
index 0000000000000..2e48bca7786a9
--- /dev/null
+++ b/libs/WindowManager/Shell/res/color/decor_button_light_color.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item app:state_task_focused="true" android:color="#FFFFFFFF" />
+    <item android:color="#33FFFFFF" />
+</selector>
\ No newline at end of file
diff --git a/libs/WindowManager/Shell/res/color/decor_caption_title_color.xml b/libs/WindowManager/Shell/res/color/decor_caption_title_color.xml
new file mode 100644
index 0000000000000..1ecc13e4da389
--- /dev/null
+++ b/libs/WindowManager/Shell/res/color/decor_caption_title_color.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto">
+     <!-- Fading the to 85% blackness -->
+    <item app:state_task_focused="true" android:color="#D8D8D8" />
+    <!-- Fading the to 95% blackness -->
+    <item android:color="#F2F2F2" />
+</selector>
diff --git a/libs/WindowManager/Shell/res/drawable/decor_caption_title.xml b/libs/WindowManager/Shell/res/drawable/decor_caption_title.xml
new file mode 100644
index 0000000000000..8207365a737d9
--- /dev/null
+++ b/libs/WindowManager/Shell/res/drawable/decor_caption_title.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<shape android:shape="rectangle"
+       android:tintMode="multiply"
+       android:tint="@color/decor_caption_title_color"
+       xmlns:android="http://schemas.android.com/apk/res/android">
+    <solid android:color="?android:attr/colorPrimary" />
+</shape>
diff --git a/libs/WindowManager/Shell/res/drawable/decor_close_button_dark.xml b/libs/WindowManager/Shell/res/drawable/decor_close_button_dark.xml
new file mode 100644
index 0000000000000..f2f1a1d55dee6
--- /dev/null
+++ b/libs/WindowManager/Shell/res/drawable/decor_close_button_dark.xml
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="32.0dp"
+        android:height="32.0dp"
+        android:viewportWidth="32.0"
+        android:viewportHeight="32.0"
+        android:tint="@color/decor_button_dark_color"
+        >
+    <group android:scaleX="0.5"
+            android:scaleY="0.5"
+            android:translateX="8.0"
+            android:translateY="8.0" >
+        <path
+            android:fillColor="@android:color/white"
+            android:pathData="M6.9,4.0l-2.9,2.9 9.1,9.1 -9.1,9.200001 2.9,2.799999 9.1,-9.1 9.1,9.1 2.9,-2.799999 -9.1,-9.200001 9.1,-9.1 -2.9,-2.9 -9.1,9.2z"/>
+    </group>
+</vector>
diff --git a/libs/WindowManager/Shell/res/drawable/decor_maximize_button_dark.xml b/libs/WindowManager/Shell/res/drawable/decor_maximize_button_dark.xml
new file mode 100644
index 0000000000000..ab4e29ac97e58
--- /dev/null
+++ b/libs/WindowManager/Shell/res/drawable/decor_maximize_button_dark.xml
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="32.0dp"
+        android:height="32.0dp"
+        android:viewportWidth="32.0"
+        android:viewportHeight="32.0"
+        android:tint="@color/decor_button_dark_color">
+    <group android:scaleX="0.5"
+            android:scaleY="0.5"
+            android:translateX="8.0"
+            android:translateY="8.0" >
+        <path
+            android:fillColor="@android:color/white"
+            android:pathData="M2.0,4.0l0.0,16.0l28.0,0.0L30.0,4.0L2.0,4.0zM26.0,16.0L6.0,16.0L6.0,8.0l20.0,0.0L26.0,16.0z"/>
+        <path
+            android:fillColor="@android:color/white"
+            android:pathData="M2.0,24.0l28.0,0.0l0.0,4.0l-28.0,0.0z"/>
+    </group>
+</vector>
+
+
diff --git a/libs/WindowManager/Shell/res/layout/caption_window_decoration.xml b/libs/WindowManager/Shell/res/layout/caption_window_decoration.xml
new file mode 100644
index 0000000000000..a112f1933dd11
--- /dev/null
+++ b/libs/WindowManager/Shell/res/layout/caption_window_decoration.xml
@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<com.android.wm.shell.windowdecor.WindowDecorLinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/caption"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:gravity="end"
+    android:background="@drawable/decor_caption_title">
+    <Button
+        android:id="@+id/maximize_window"
+        android:layout_width="32dp"
+        android:layout_height="32dp"
+        android:layout_margin="5dp"
+        android:padding="4dp"
+        android:layout_gravity="center_vertical|end"
+        android:contentDescription="@string/maximize_button_text"
+        android:background="@drawable/decor_maximize_button_dark"
+        android:duplicateParentState="true"/>
+    <Button
+        android:id="@+id/close_window"
+        android:layout_width="32dp"
+        android:layout_height="32dp"
+        android:layout_margin="5dp"
+        android:padding="4dp"
+        android:layout_gravity="center_vertical|end"
+        android:contentDescription="@string/close_button_text"
+        android:background="@drawable/decor_close_button_dark"
+        android:duplicateParentState="true"/>
+</com.android.wm.shell.windowdecor.WindowDecorLinearLayout>
+
diff --git a/libs/WindowManager/Shell/res/values/attrs.xml b/libs/WindowManager/Shell/res/values/attrs.xml
index 4aaeef8afcb0e..2aad4c1c18051 100644
--- a/libs/WindowManager/Shell/res/values/attrs.xml
+++ b/libs/WindowManager/Shell/res/values/attrs.xml
@@ -19,4 +19,8 @@
         <attr name="icon" format="reference" />
         <attr name="text" format="string" />
     </declare-styleable>
+
+    <declare-styleable name="MessageState">
+        <attr name="state_task_focused" format="boolean"/>
+    </declare-styleable>
 </resources>
diff --git a/libs/WindowManager/Shell/res/values/strings.xml b/libs/WindowManager/Shell/res/values/strings.xml
index a24311fb1f21b..b2f09895d7d8a 100644
--- a/libs/WindowManager/Shell/res/values/strings.xml
+++ b/libs/WindowManager/Shell/res/values/strings.xml
@@ -186,4 +186,12 @@
     <!-- Button text for dismissing the letterbox education dialog. [CHAR LIMIT=20] -->
     <string name="letterbox_education_got_it">Got it</string>
 
+    <!-- Accessibility description of the letterbox education toast expand to dialog button. [CHAR LIMIT=NONE] -->
+    <string name="letterbox_education_expand_button_description">Expand for more information.</string>
+
+    <!-- Freeform window caption strings -->
+    <!-- Accessibility text for the maximize window button [CHAR LIMIT=NONE] -->
+    <string name="maximize_button_text">Maximize</string>
+    <!-- Accessibility text for the close window button [CHAR LIMIT=NONE] -->
+    <string name="close_button_text">Close</string>
 </resources>
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/ShellInitImpl.java b/libs/WindowManager/Shell/src/com/android/wm/shell/ShellInitImpl.java
index f6a3e7fb54d91..bebafb9dd39af 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/ShellInitImpl.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/ShellInitImpl.java
@@ -57,7 +57,7 @@ public class ShellInitImpl {
     private final FullscreenTaskListener mFullscreenTaskListener;
     private final Optional<FullscreenUnfoldController> mFullscreenUnfoldController;
     private final Optional<UnfoldTransitionHandler> mUnfoldTransitionHandler;
-    private final Optional<FreeformTaskListener> mFreeformTaskListenerOptional;
+    private final Optional<FreeformTaskListener<?>> mFreeformTaskListenerOptional;
     private final ShellExecutor mMainExecutor;
     private final Transitions mTransitions;
     private final StartingWindowController mStartingWindow;
@@ -78,7 +78,7 @@ public class ShellInitImpl {
             FullscreenTaskListener fullscreenTaskListener,
             Optional<FullscreenUnfoldController> fullscreenUnfoldTransitionController,
             Optional<UnfoldTransitionHandler> unfoldTransitionHandler,
-            Optional<FreeformTaskListener> freeformTaskListenerOptional,
+            Optional<FreeformTaskListener<?>> freeformTaskListenerOptional,
             Optional<RecentTasksController> recentTasks,
             Transitions transitions,
             StartingWindowController startingWindow,
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellBaseModule.java b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellBaseModule.java
index 1d10bbe37438c..12bff8d4a3602 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellBaseModule.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellBaseModule.java
@@ -347,12 +347,12 @@ public abstract class WMShellBaseModule {
     // Workaround for dynamic overriding with a default implementation, see {@link DynamicOverride}
     @BindsOptionalOf
     @DynamicOverride
-    abstract FreeformTaskListener optionalFreeformTaskListener();
+    abstract FreeformTaskListener<?> optionalFreeformTaskListener();
 
     @WMSingleton
     @Provides
-    static Optional<FreeformTaskListener> provideFreeformTaskListener(
-            @DynamicOverride Optional<FreeformTaskListener> freeformTaskListener,
+    static Optional<FreeformTaskListener<?>> provideFreeformTaskListener(
+            @DynamicOverride Optional<FreeformTaskListener<?>> freeformTaskListener,
             Context context) {
         if (FreeformTaskListener.isFreeformEnabled(context)) {
             return freeformTaskListener;
@@ -642,7 +642,7 @@ public abstract class WMShellBaseModule {
             FullscreenTaskListener fullscreenTaskListener,
             Optional<FullscreenUnfoldController> appUnfoldTransitionController,
             Optional<UnfoldTransitionHandler> unfoldTransitionHandler,
-            Optional<FreeformTaskListener> freeformTaskListener,
+            Optional<FreeformTaskListener<?>> freeformTaskListener,
             Optional<RecentTasksController> recentTasksOptional,
             Transitions transitions,
             StartingWindowController startingWindow,
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
index 47c9214bcae9f..a4d1ce18f32b6 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
@@ -74,6 +74,8 @@ import com.android.wm.shell.unfold.ShellUnfoldProgressProvider;
 import com.android.wm.shell.unfold.UnfoldBackgroundController;
 import com.android.wm.shell.unfold.UnfoldTransitionHandler;
 import com.android.wm.shell.unfold.animation.FullscreenUnfoldTaskAnimator;
+import com.android.wm.shell.windowdecor.CaptionWindowDecorViewModel;
+import com.android.wm.shell.windowdecor.WindowDecorViewModel;
 
 import java.util.Optional;
 
@@ -127,6 +129,24 @@ public class WMShellModule {
                 taskViewTransitions, syncQueue);
     }
 
+    //
+    // Window decoration
+    //
+
+    @WMSingleton
+    @Provides
+    static WindowDecorViewModel<?> provideWindowDecorViewModel(
+            Context context,
+            ShellTaskOrganizer taskOrganizer,
+            DisplayController displayController,
+            SyncTransactionQueue syncQueue) {
+        return new CaptionWindowDecorViewModel(
+                        context,
+                        taskOrganizer,
+                        displayController,
+                        syncQueue);
+    }
+
     //
     // Freeform
     //
@@ -134,9 +154,10 @@ public class WMShellModule {
     @WMSingleton
     @Provides
     @DynamicOverride
-    static FreeformTaskListener provideFreeformTaskListener(
+    static FreeformTaskListener<?> provideFreeformTaskListener(
+            WindowDecorViewModel<?> windowDecorViewModel,
             SyncTransactionQueue syncQueue) {
-        return new FreeformTaskListener(syncQueue);
+        return new FreeformTaskListener<>(windowDecorViewModel, syncQueue);
     }
 
     //
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
index fef9be36a35f7..fb26cb64f0e71 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
@@ -21,8 +21,6 @@ import static android.provider.Settings.Global.DEVELOPMENT_ENABLE_FREEFORM_WINDO
 
 import android.app.ActivityManager.RunningTaskInfo;
 import android.content.Context;
-import android.graphics.Point;
-import android.graphics.Rect;
 import android.provider.Settings;
 import android.util.Slog;
 import android.util.SparseArray;
@@ -32,26 +30,35 @@ import com.android.internal.protolog.common.ProtoLog;
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.common.SyncTransactionQueue;
 import com.android.wm.shell.protolog.ShellProtoLogGroup;
+import com.android.wm.shell.windowdecor.WindowDecorViewModel;
 
 import java.io.PrintWriter;
 
 /**
  * {@link ShellTaskOrganizer.TaskListener} for {@link
  * ShellTaskOrganizer#TASK_LISTENER_TYPE_FREEFORM}.
+ *
+ * @param <T> the type of window decoration instance
  */
-public class FreeformTaskListener implements ShellTaskOrganizer.TaskListener {
+public class FreeformTaskListener<T extends AutoCloseable>
+        implements ShellTaskOrganizer.TaskListener {
     private static final String TAG = "FreeformTaskListener";
 
+    private final WindowDecorViewModel<T> mWindowDecorationViewModel;
     private final SyncTransactionQueue mSyncQueue;
 
-    private final SparseArray<State> mTasks = new SparseArray<>();
+    private final SparseArray<State<T>> mTasks = new SparseArray<>();
 
-    private static class State {
+    private static class State<T extends AutoCloseable> {
         RunningTaskInfo mTaskInfo;
         SurfaceControl mLeash;
+        T mWindowDecoration;
     }
 
-    public FreeformTaskListener(SyncTransactionQueue syncQueue) {
+    public FreeformTaskListener(
+            WindowDecorViewModel<T> windowDecorationViewModel,
+            SyncTransactionQueue syncQueue) {
+        mWindowDecorationViewModel = windowDecorationViewModel;
         mSyncQueue = syncQueue;
     }
 
@@ -62,23 +69,17 @@ public class FreeformTaskListener implements ShellTaskOrganizer.TaskListener {
         }
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Appeared: #%d",
                 taskInfo.taskId);
-        final State state = new State();
+        final State<T> state = new State<>();
         state.mTaskInfo = taskInfo;
         state.mLeash = leash;
+        state.mWindowDecoration =
+                mWindowDecorationViewModel.createWindowDecoration(taskInfo, leash);
         mTasks.put(taskInfo.taskId, state);
-
-        final Rect taskBounds = taskInfo.configuration.windowConfiguration.getBounds();
-        mSyncQueue.runInSync(t -> {
-            Point taskPosition = taskInfo.positionInParent;
-            t.setPosition(leash, taskPosition.x, taskPosition.y)
-                    .setWindowCrop(leash, taskBounds.width(), taskBounds.height())
-                    .show(leash);
-        });
     }
 
     @Override
     public void onTaskVanished(RunningTaskInfo taskInfo) {
-        State state = mTasks.get(taskInfo.taskId);
+        State<T> state = mTasks.get(taskInfo.taskId);
         if (state == null) {
             Slog.e(TAG, "Task already vanished: #" + taskInfo.taskId);
             return;
@@ -86,11 +87,17 @@ public class FreeformTaskListener implements ShellTaskOrganizer.TaskListener {
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Vanished: #%d",
                 taskInfo.taskId);
         mTasks.remove(taskInfo.taskId);
+
+        try {
+            state.mWindowDecoration.close();
+        } catch (Exception e) {
+            Slog.e(TAG, "Failed to release window decoration.", e);
+        }
     }
 
     @Override
     public void onTaskInfoChanged(RunningTaskInfo taskInfo) {
-        State state = mTasks.get(taskInfo.taskId);
+        State<T> state = mTasks.get(taskInfo.taskId);
         if (state == null) {
             throw new RuntimeException(
                     "Task info changed before appearing: #" + taskInfo.taskId);
@@ -98,15 +105,9 @@ public class FreeformTaskListener implements ShellTaskOrganizer.TaskListener {
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Info Changed: #%d",
                 taskInfo.taskId);
         state.mTaskInfo = taskInfo;
-
-        final Rect taskBounds = taskInfo.configuration.windowConfiguration.getBounds();
-        final SurfaceControl leash = state.mLeash;
-        mSyncQueue.runInSync(t -> {
-            Point taskPosition = taskInfo.positionInParent;
-            t.setPosition(leash, taskPosition.x, taskPosition.y)
-                    .setWindowCrop(leash, taskBounds.width(), taskBounds.height())
-                    .show(leash);
-        });
+        mWindowDecorationViewModel.onTaskInfoChanged(state.mTaskInfo, state.mWindowDecoration);
+        ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Info Changed: #%d",
+                taskInfo.taskId);
     }
 
     @Override
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
new file mode 100644
index 0000000000000..d678f031698e8
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import static android.app.WindowConfiguration.WINDOWING_MODE_FREEFORM;
+import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
+import static android.app.WindowConfiguration.WINDOWING_MODE_UNDEFINED;
+
+import android.app.ActivityManager;
+import android.app.ActivityManager.RunningTaskInfo;
+import android.app.ActivityTaskManager;
+import android.content.Context;
+import android.view.MotionEvent;
+import android.view.SurfaceControl;
+import android.view.View;
+import android.window.WindowContainerToken;
+import android.window.WindowContainerTransaction;
+
+import com.android.wm.shell.R;
+import com.android.wm.shell.ShellTaskOrganizer;
+import com.android.wm.shell.common.DisplayController;
+import com.android.wm.shell.common.SyncTransactionQueue;
+
+/**
+ * View model for the window decoration with a caption and shadows. Works with
+ * {@link CaptionWindowDecoration}.
+ */
+public class CaptionWindowDecorViewModel implements WindowDecorViewModel<CaptionWindowDecoration> {
+    private final ActivityTaskManager mActivityTaskManager;
+    private final ShellTaskOrganizer mTaskOrganizer;
+    private final Context mContext;
+    private final DisplayController mDisplayController;
+    private final SyncTransactionQueue mSyncQueue;
+
+    public CaptionWindowDecorViewModel(
+            Context context,
+            ShellTaskOrganizer taskOrganizer,
+            DisplayController displayController,
+            SyncTransactionQueue syncQueue) {
+        mContext = context;
+        mActivityTaskManager = mContext.getSystemService(ActivityTaskManager.class);
+        mTaskOrganizer = taskOrganizer;
+        mDisplayController = displayController;
+        mSyncQueue = syncQueue;
+    }
+
+    @Override
+    public CaptionWindowDecoration createWindowDecoration(
+            ActivityManager.RunningTaskInfo taskInfo, SurfaceControl taskSurface) {
+        final CaptionWindowDecoration windowDecoration = new CaptionWindowDecoration(
+                mContext,
+                mDisplayController,
+                mTaskOrganizer,
+                taskInfo,
+                taskSurface,
+                mSyncQueue);
+        CaptionTouchEventListener touchEventListener = new CaptionTouchEventListener(taskInfo);
+        windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
+        onTaskInfoChanged(taskInfo, windowDecoration);
+        return windowDecoration;
+    }
+
+    @Override
+    public void onTaskInfoChanged(RunningTaskInfo taskInfo, CaptionWindowDecoration decoration) {
+        decoration.relayout(taskInfo);
+
+        int statusBarColor = taskInfo.taskDescription.getStatusBarColor();
+        decoration.setCaptionColor(statusBarColor);
+    }
+
+    private class CaptionTouchEventListener implements
+            View.OnClickListener, View.OnTouchListener {
+
+        private final int mTaskId;
+        private final WindowContainerToken mTaskToken;
+
+        private CaptionTouchEventListener(RunningTaskInfo taskInfo) {
+            mTaskId = taskInfo.taskId;
+            mTaskToken = taskInfo.token;
+        }
+
+        @Override
+        public void onClick(View v) {
+            int id = v.getId();
+            if (id == R.id.close_window) {
+                mActivityTaskManager.removeTask(mTaskId);
+            } else if (id == R.id.maximize_window) {
+                WindowContainerTransaction wct = new WindowContainerTransaction();
+                RunningTaskInfo taskInfo = mTaskOrganizer.getRunningTaskInfo(mTaskId);
+                int targetWindowingMode = taskInfo.getWindowingMode() != WINDOWING_MODE_FULLSCREEN
+                        ? WINDOWING_MODE_FULLSCREEN : WINDOWING_MODE_FREEFORM;
+                int displayWindowingMode =
+                        taskInfo.configuration.windowConfiguration.getDisplayWindowingMode();
+                wct.setWindowingMode(mTaskToken,
+                        targetWindowingMode == displayWindowingMode
+                            ? WINDOWING_MODE_UNDEFINED : targetWindowingMode);
+                if (targetWindowingMode == WINDOWING_MODE_FULLSCREEN) {
+                    wct.setBounds(mTaskToken, null);
+                }
+                mSyncQueue.queue(wct);
+            }
+        }
+
+        @Override
+        public boolean onTouch(View v, MotionEvent e) {
+            if (v.getId() != R.id.caption) {
+                return false;
+            }
+            if (e.getAction() != MotionEvent.ACTION_DOWN) {
+                return false;
+            }
+            RunningTaskInfo taskInfo = mTaskOrganizer.getRunningTaskInfo(mTaskId);
+            if (taskInfo.isFocused) {
+                return false;
+            }
+            WindowContainerTransaction wct = new WindowContainerTransaction();
+            wct.reorder(mTaskToken, true /* onTop */);
+            mSyncQueue.queue(wct);
+            return true;
+        }
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
new file mode 100644
index 0000000000000..569be23b9f521
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import android.app.ActivityManager;
+import android.content.Context;
+import android.content.res.ColorStateList;
+import android.graphics.Color;
+import android.graphics.Rect;
+import android.graphics.drawable.GradientDrawable;
+import android.graphics.drawable.VectorDrawable;
+import android.view.SurfaceControl;
+import android.view.View;
+import android.window.WindowContainerTransaction;
+
+import com.android.wm.shell.R;
+import com.android.wm.shell.ShellTaskOrganizer;
+import com.android.wm.shell.common.DisplayController;
+import com.android.wm.shell.common.SyncTransactionQueue;
+
+/**
+ * Defines visuals and behaviors of a window decoration of a caption bar and shadows. It works with
+ * {@link CaptionWindowDecorViewModel}. The caption bar contains maximize and close buttons.
+ *
+ * {@link CaptionWindowDecorViewModel} can change the color of the caption bar based on the foremost
+ * app's request through {@link #setCaptionColor(int)}, in which it changes the foreground color of
+ * caption buttons according to the luminance of the background.
+ *
+ * The shadow's thickness is 20dp when the window is in focus and 5dp when the window isn't.
+ */
+public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearLayout> {
+    // The thickness of shadows of a window that has focus in DIP.
+    private static final int DECOR_SHADOW_FOCUSED_THICKNESS_IN_DIP = 20;
+    // The thickness of shadows of a window that doesn't have focus in DIP.
+    private static final int DECOR_SHADOW_UNFOCUSED_THICKNESS_IN_DIP = 5;
+
+    private static final int DECOR_CAPTION_HEIGHT_IN_DIP = 42;
+    private static final Rect EMPTY_OUTSET = new Rect();
+
+    private final SyncTransactionQueue mSyncQueue;
+
+    private View.OnClickListener mOnCaptionButtonClickListener;
+    private View.OnTouchListener mOnCaptionTouchListener;
+
+    private final WindowDecoration.RelayoutResult<WindowDecorLinearLayout> mResult =
+            new WindowDecoration.RelayoutResult<>();
+
+    CaptionWindowDecoration(
+            Context context,
+            DisplayController displayController,
+            ShellTaskOrganizer taskOrganizer,
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SyncTransactionQueue syncQueue) {
+        super(context, displayController, taskOrganizer, taskInfo, taskSurface);
+
+        mSyncQueue = syncQueue;
+    }
+
+    void setCaptionListeners(
+            View.OnClickListener onCaptionButtonClickListener,
+            View.OnTouchListener onCaptionTouchListener) {
+        mOnCaptionButtonClickListener = onCaptionButtonClickListener;
+        mOnCaptionTouchListener = onCaptionTouchListener;
+    }
+
+    void relayout(ActivityManager.RunningTaskInfo taskInfo) {
+        final int shadowRadiusDp = taskInfo.isFocused
+                ? DECOR_SHADOW_FOCUSED_THICKNESS_IN_DIP : DECOR_SHADOW_UNFOCUSED_THICKNESS_IN_DIP;
+
+        WindowDecorLinearLayout oldRootView = mResult.mRootView;
+        final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
+        final WindowContainerTransaction wct = new WindowContainerTransaction();
+        relayout(taskInfo, R.layout.caption_window_decoration, oldRootView,
+                DECOR_CAPTION_HEIGHT_IN_DIP, EMPTY_OUTSET, shadowRadiusDp, t, wct, mResult);
+        taskInfo = null; // Clear it just in case we use it accidentally
+
+        mSyncQueue.runInSync(transaction -> {
+            transaction.merge(t);
+            t.close();
+
+            mTaskOrganizer.applyTransaction(wct);
+        });
+
+        if (mResult.mRootView == null) {
+            return;
+        }
+        if (oldRootView != mResult.mRootView) {
+            setupRootView();
+        }
+    }
+
+    /**
+     * Sets up listeners when a new root view is created.
+     */
+    private void setupRootView() {
+        View caption = mResult.mRootView.findViewById(R.id.caption);
+
+        caption.setOnTouchListener(mOnCaptionTouchListener);
+        View maximize = caption.findViewById(R.id.maximize_window);
+        maximize.setOnClickListener(mOnCaptionButtonClickListener);
+        View close = caption.findViewById(R.id.close_window);
+        close.setOnClickListener(mOnCaptionButtonClickListener);
+    }
+
+    void setCaptionColor(int captionColor) {
+        if (mResult.mRootView == null) {
+            return;
+        }
+
+        View caption = mResult.mRootView.findViewById(R.id.caption);
+        GradientDrawable captionDrawable = (GradientDrawable) caption.getBackground();
+        captionDrawable.setColor(captionColor);
+
+        int buttonTintColorRes =
+                Color.valueOf(captionColor).luminance() < 0.5
+                        ? R.color.decor_button_light_color
+                        : R.color.decor_button_dark_color;
+        ColorStateList buttonTintColor =
+                caption.getResources().getColorStateList(buttonTintColorRes, null /* theme */);
+        View maximize = caption.findViewById(R.id.maximize_window);
+        VectorDrawable maximizeBackground = (VectorDrawable) maximize.getBackground();
+        maximizeBackground.setTintList(buttonTintColor);
+
+        View close = caption.findViewById(R.id.close_window);
+        VectorDrawable closeBackground = (VectorDrawable) close.getBackground();
+        closeBackground.setTintList(buttonTintColor);
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskFocusStateConsumer.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskFocusStateConsumer.java
new file mode 100644
index 0000000000000..1c61802bbd5ce
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskFocusStateConsumer.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+interface TaskFocusStateConsumer {
+    void setTaskFocusState(boolean focused);
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorLinearLayout.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorLinearLayout.java
new file mode 100644
index 0000000000000..6d8001a2f92b9
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorLinearLayout.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.widget.LinearLayout;
+
+import androidx.annotation.Nullable;
+
+import com.android.wm.shell.R;
+
+/**
+ * A {@link LinearLayout} that takes an additional task focused drawable state. The new state is
+ * used to select the correct background color for views in the window decoration.
+ */
+public class WindowDecorLinearLayout extends LinearLayout implements TaskFocusStateConsumer {
+    private static final int[] TASK_FOCUSED_STATE = { R.attr.state_task_focused };
+
+    private boolean mIsTaskFocused;
+
+    public WindowDecorLinearLayout(Context context) {
+        super(context);
+    }
+
+    public WindowDecorLinearLayout(Context context,
+            @Nullable AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public WindowDecorLinearLayout(Context context, @Nullable AttributeSet attrs,
+            int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    public WindowDecorLinearLayout(Context context, AttributeSet attrs, int defStyleAttr,
+            int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    @Override
+    public void setTaskFocusState(boolean focused) {
+        mIsTaskFocused = focused;
+
+        refreshDrawableState();
+    }
+
+    @Override
+    protected int[] onCreateDrawableState(int extraSpace) {
+        if (!mIsTaskFocused) {
+            return super.onCreateDrawableState(extraSpace);
+        }
+
+        final int[] states = super.onCreateDrawableState(extraSpace + 1);
+        mergeDrawableStates(states, TASK_FOCUSED_STATE);
+        return states;
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
new file mode 100644
index 0000000000000..6f9ceff722aca
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import android.app.ActivityManager;
+import android.view.SurfaceControl;
+
+/**
+ * The interface used by some {@link com.android.wm.shell.ShellTaskOrganizer.TaskListener} to help
+ * customize {@link WindowDecoration}. Its implementations are responsible to interpret user's
+ * interactions with UI widgets in window decorations and send corresponding requests to system
+ * servers.
+ *
+ * @param <T> The actual decoration type
+ */
+public interface WindowDecorViewModel<T extends AutoCloseable> {
+
+    /**
+     * Creates a window decoration for the given task.
+     *
+     * @param taskInfo the initial task info of the task
+     * @param taskSurface the surface of the task
+     * @return the window decoration object
+     */
+    T createWindowDecoration(ActivityManager.RunningTaskInfo taskInfo, SurfaceControl taskSurface);
+
+    /**
+     * Notifies a task info update on the given task, with the window decoration created previously
+     * for this task by {@link #createWindowDecoration}.
+     *
+     * @param taskInfo the new task info of the task
+     * @param windowDecoration the window decoration created for the task
+     */
+    void onTaskInfoChanged(ActivityManager.RunningTaskInfo taskInfo, T windowDecoration);
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
new file mode 100644
index 0000000000000..00ecdf481343e
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import android.app.ActivityManager.RunningTaskInfo;
+import android.content.Context;
+import android.content.res.Configuration;
+import android.graphics.Color;
+import android.graphics.PixelFormat;
+import android.graphics.Point;
+import android.graphics.Rect;
+import android.util.DisplayMetrics;
+import android.view.Display;
+import android.view.InsetsState;
+import android.view.LayoutInflater;
+import android.view.SurfaceControl;
+import android.view.SurfaceControlViewHost;
+import android.view.View;
+import android.view.WindowManager;
+import android.view.WindowlessWindowManager;
+import android.window.WindowContainerTransaction;
+
+import com.android.wm.shell.ShellTaskOrganizer;
+import com.android.wm.shell.common.DisplayController;
+
+/**
+ * Manages a container surface and a windowless window to show window decoration. Responsible to
+ * update window decoration window state and layout parameters on task info changes and so that
+ * window decoration is in correct state and bounds.
+ *
+ * The container surface is a child of the task display area in the same display, so that window
+ * decorations can be drawn out of the task bounds and receive input events from out of the task
+ * bounds to support drag resizing.
+ *
+ * The windowless window that hosts window decoration is positioned in front of all activities, to
+ * allow the foreground activity to draw its own background behind window decorations, such as
+ * the window captions.
+ *
+ * @param <T> The type of the root view
+ */
+public class WindowDecoration<T extends View & TaskFocusStateConsumer> implements AutoCloseable {
+    private static final int[] CAPTION_INSETS_TYPES = { InsetsState.ITYPE_CAPTION_BAR };
+
+    /**
+     * System-wide context. Only used to create context with overridden configurations.
+     */
+    final Context mContext;
+    final DisplayController mDisplayController;
+    final ShellTaskOrganizer mTaskOrganizer;
+
+    RunningTaskInfo mTaskInfo;
+    final SurfaceControl mTaskSurface;
+
+    Display mDisplay;
+    Context mDecorWindowContext;
+    SurfaceControl mDecorationContainerSurface;
+    SurfaceControl mTaskBackgroundSurface;
+
+    private CaptionWindowManager mCaptionWindowManager;
+    private SurfaceControlViewHost mViewHost;
+
+    private final Rect mCaptionInsetsRect = new Rect();
+    private final Rect mTaskSurfaceCrop = new Rect();
+    private final float[] mTmpColor = new float[3];
+
+    WindowDecoration(
+            Context context,
+            DisplayController displayController,
+            ShellTaskOrganizer taskOrganizer,
+            RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface) {
+        mContext = context;
+        mDisplayController = displayController;
+        mTaskOrganizer = taskOrganizer;
+        mTaskInfo = taskInfo;
+        mTaskSurface = taskSurface;
+
+        mDisplay = mDisplayController.getDisplay(mTaskInfo.displayId);
+        mDecorWindowContext = mContext.createConfigurationContext(mTaskInfo.getConfiguration());
+
+        // Put caption under task surface because ViewRootImpl sets the destination frame of
+        // windowless window layers and BLASTBufferQueue#update() doesn't support offset.
+        mCaptionWindowManager =
+                new CaptionWindowManager(mTaskInfo.getConfiguration(), mTaskSurface);
+    }
+
+    void relayout(RunningTaskInfo taskInfo, int layoutResId, T rootView, float captionHeightDp,
+            Rect outsetsDp, float shadowRadiusDp, SurfaceControl.Transaction t,
+            WindowContainerTransaction wct, RelayoutResult<T> outResult) {
+        outResult.reset();
+
+        final Configuration oldTaskConfig = mTaskInfo.getConfiguration();
+        if (taskInfo != null) {
+            mTaskInfo = taskInfo;
+        }
+
+        if (!mTaskInfo.isVisible) {
+            close();
+            t.hide(mTaskSurface);
+            return;
+        }
+
+        if (rootView == null && layoutResId == 0) {
+            throw new IllegalArgumentException("layoutResId and rootView can't both be invalid.");
+        }
+
+        outResult.mRootView = rootView;
+        rootView = null; // Clear it just in case we use it accidentally
+        final Configuration taskConfig = mTaskInfo.getConfiguration();
+        if (oldTaskConfig.densityDpi != taskConfig.densityDpi
+                || mDisplay.getDisplayId() != mTaskInfo.displayId) {
+            close();
+
+            mDisplay = mDisplayController.getDisplay(mTaskInfo.displayId);
+            mDecorWindowContext = mContext.createConfigurationContext(taskConfig);
+            if (layoutResId != 0) {
+                outResult.mRootView =
+                        (T) LayoutInflater.from(mDecorWindowContext).inflate(layoutResId, null);
+            }
+        }
+
+        if (outResult.mRootView == null) {
+            outResult.mRootView =
+                    (T) LayoutInflater.from(mDecorWindowContext).inflate(layoutResId, null);
+        }
+
+        // DecorationContainerSurface
+        if (mDecorationContainerSurface == null) {
+            final SurfaceControl.Builder builder = new SurfaceControl.Builder();
+            mDecorationContainerSurface = builder
+                    .setName("Decor container of Task=" + mTaskInfo.taskId)
+                    .setContainerLayer()
+                    .setParent(mTaskSurface)
+                    .build();
+
+            t.setTrustedOverlay(mDecorationContainerSurface, true);
+        }
+
+        final Rect taskBounds = taskConfig.windowConfiguration.getBounds();
+        outResult.mDensity = taskConfig.densityDpi * DisplayMetrics.DENSITY_DEFAULT_SCALE;
+        final int decorContainerOffsetX = -(int) (outsetsDp.left * outResult.mDensity);
+        final int decorContainerOffsetY = -(int) (outsetsDp.top * outResult.mDensity);
+        outResult.mWidth = taskBounds.width()
+                + (int) (outsetsDp.right * outResult.mDensity)
+                - decorContainerOffsetX;
+        outResult.mHeight = taskBounds.height()
+                + (int) (outsetsDp.bottom * outResult.mDensity)
+                - decorContainerOffsetY;
+        t.setPosition(mDecorationContainerSurface, decorContainerOffsetX, decorContainerOffsetY)
+                .setWindowCrop(mDecorationContainerSurface, outResult.mWidth, outResult.mHeight)
+                .setLayer(mDecorationContainerSurface, mTaskInfo.numActivities + 1)
+                .show(mDecorationContainerSurface);
+
+        // TaskBackgroundSurface
+        if (mTaskBackgroundSurface == null) {
+            final SurfaceControl.Builder builder = new SurfaceControl.Builder();
+            mTaskBackgroundSurface = builder
+                    .setName("Background of Task=" + mTaskInfo.taskId)
+                    .setEffectLayer()
+                    .setParent(mTaskSurface)
+                    .build();
+        }
+
+        float shadowRadius = outResult.mDensity * shadowRadiusDp;
+        int backgroundColorInt = mTaskInfo.taskDescription.getBackgroundColor();
+        mTmpColor[0] = Color.red(backgroundColorInt);
+        mTmpColor[1] = Color.green(backgroundColorInt);
+        mTmpColor[2] = Color.blue(backgroundColorInt);
+        t.setCrop(mTaskBackgroundSurface, taskBounds)
+                .setShadowRadius(mTaskBackgroundSurface, shadowRadius)
+                .setColor(mTaskBackgroundSurface, mTmpColor);
+
+        // Caption view
+        mCaptionWindowManager.setConfiguration(taskConfig);
+        final int captionHeight = (int) Math.ceil(captionHeightDp * outResult.mDensity);
+        final WindowManager.LayoutParams lp =
+                new WindowManager.LayoutParams(taskBounds.width(), captionHeight,
+                        WindowManager.LayoutParams.TYPE_APPLICATION,
+                        WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, PixelFormat.TRANSPARENT);
+        lp.setTitle("Caption of Task=" + mTaskInfo.taskId);
+        lp.setTrustedOverlay();
+        if (mViewHost == null) {
+            mViewHost = new SurfaceControlViewHost(mDecorWindowContext, mDisplay,
+                    mCaptionWindowManager, true);
+            mViewHost.setView(outResult.mRootView, lp);
+        } else {
+            mViewHost.relayout(lp);
+        }
+
+        outResult.mRootView.setTaskFocusState(mTaskInfo.isFocused);
+
+        // Caption insets
+        mCaptionInsetsRect.set(taskBounds);
+        mCaptionInsetsRect.bottom = mCaptionInsetsRect.top + captionHeight;
+        wct.addRectInsetsProvider(mTaskInfo.token, mCaptionInsetsRect, CAPTION_INSETS_TYPES);
+
+        // Task surface itself
+        Point taskPosition = mTaskInfo.positionInParent;
+        mTaskSurfaceCrop.set(
+                decorContainerOffsetX,
+                decorContainerOffsetY,
+                outResult.mWidth + decorContainerOffsetX,
+                outResult.mHeight + decorContainerOffsetY);
+        t.setPosition(mTaskSurface, taskPosition.x, taskPosition.y)
+                .setCrop(mTaskSurface, mTaskSurfaceCrop)
+                .show(mTaskSurface);
+    }
+
+    @Override
+    public void close() {
+        if (mViewHost != null) {
+            mViewHost.release();
+            mViewHost = null;
+        }
+
+        if (mDecorationContainerSurface != null) {
+            mDecorationContainerSurface.release();
+            mDecorationContainerSurface = null;
+        }
+
+        if (mTaskBackgroundSurface != null) {
+            mTaskBackgroundSurface.release();
+            mTaskBackgroundSurface = null;
+        }
+    }
+
+    static class RelayoutResult<T extends View & TaskFocusStateConsumer> {
+        int mWidth;
+        int mHeight;
+        float mDensity;
+        T mRootView;
+
+        void reset() {
+            mWidth = 0;
+            mHeight = 0;
+            mDensity = 0;
+            mRootView = null;
+        }
+    }
+
+    private static class CaptionWindowManager extends WindowlessWindowManager {
+        CaptionWindowManager(Configuration config, SurfaceControl rootSurface) {
+            super(config, rootSurface, null /* hostInputToken */);
+        }
+
+        @Override
+        public void setConfiguration(Configuration configuration) {
+            super.setConfiguration(configuration);
+        }
+    }
+}
diff --git a/services/core/java/com/android/server/wm/Task.java b/services/core/java/com/android/server/wm/Task.java
index 7c1488b71bf58..fc1b89348c250 100644
--- a/services/core/java/com/android/server/wm/Task.java
+++ b/services/core/java/com/android/server/wm/Task.java
@@ -69,8 +69,6 @@ import static android.view.WindowManager.TRANSIT_TO_BACK;
 import static android.view.WindowManager.TRANSIT_TO_FRONT;
 import static android.window.DisplayAreaOrganizer.FEATURE_UNDEFINED;
 
-import static com.android.internal.policy.DecorView.DECOR_SHADOW_FOCUSED_HEIGHT_IN_DIP;
-import static com.android.internal.policy.DecorView.DECOR_SHADOW_UNFOCUSED_HEIGHT_IN_DIP;
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_ADD_REMOVE;
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_BACK_PREVIEW;
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_LOCKTASK;
@@ -131,7 +129,6 @@ import static com.android.server.wm.WindowContainerChildProto.TASK;
 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_ROOT_TASK;
 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_TASK_MOVEMENT;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
-import static com.android.server.wm.WindowManagerService.dipToPixel;
 
 import static java.lang.Integer.MAX_VALUE;
 
@@ -3277,7 +3274,6 @@ class Task extends TaskFragment {
         }
 
         final SurfaceControl.Transaction t = getSyncTransaction();
-        updateShadowsRadius(isFocused(), t);
 
         if (mDimmer.updateDims(t, mTmpDimBoundsRect)) {
             scheduleAnimation();
@@ -4248,49 +4244,11 @@ class Task extends TaskFragment {
         return getActivity(ActivityRecord::isVisible) != null;
     }
 
-    /**
-     * @return the desired shadow radius in pixels for the current task.
-     */
-    private float getShadowRadius(boolean taskIsFocused) {
-        int elevation = 0;
-
-        // Get elevation for a specific windowing mode.
-        if (inFreeformWindowingMode()) {
-            elevation = taskIsFocused
-                    ? DECOR_SHADOW_FOCUSED_HEIGHT_IN_DIP : DECOR_SHADOW_UNFOCUSED_HEIGHT_IN_DIP;
-        } else {
-            // For all other windowing modes, do not draw a shadow.
-            return 0;
-        }
-
-        // If the task has no visible children, do not draw a shadow.
-        if (!hasVisibleChildren()) {
-            return 0;
-        }
-
-        return dipToPixel(elevation, getDisplayContent().getDisplayMetrics());
-    }
-
-    /**
-     * Update the length of the shadow if needed based on windowing mode and task focus state.
-     */
-    private void updateShadowsRadius(boolean taskIsFocused,
-            SurfaceControl.Transaction pendingTransaction) {
-        if (!isRootTask()) return;
-
-        final float newShadowRadius = getShadowRadius(taskIsFocused);
-        if (mShadowRadius != newShadowRadius) {
-            mShadowRadius = newShadowRadius;
-            pendingTransaction.setShadowRadius(getSurfaceControl(), mShadowRadius);
-        }
-    }
-
     /**
      * Called on the task when it gained or lost focus.
      * @param hasFocus
      */
     void onAppFocusChanged(boolean hasFocus) {
-        updateShadowsRadius(hasFocus, getSyncTransaction());
         dispatchTaskInfoChangedIfNeeded(false /* force */);
     }
 

From f5751858b38021f365ddb5da1067ad128cdae3cc Mon Sep 17 00:00:00 2001
From: Garfield Tan <xutan@google.com>
Date: Wed, 25 Aug 2021 11:16:00 -0700
Subject: [PATCH 2/2] Support moving and resizing freeform windows

Instead of an InputMonitor for the entire display, we use window
decoration surface to monitor window resizing gestures. This allows us
to consolidate hit test to InputFlinger.

There is an issue that gesture monitor for gesture nav steals touches
from the resize window while resizing if user moves pointers too fast.

Bug: 165794880
Test: Drag resize works.
Change-Id: I2685e074dd02af55928d20a93f7c0690cc498fc5
---
 .../wm/shell/dagger/WMShellModule.java        |   2 +
 .../CaptionWindowDecorViewModel.java          |  42 ++-
 .../windowdecor/CaptionWindowDecoration.java  |  60 +++-
 .../shell/windowdecor/DragResizeCallback.java |  46 +++
 .../windowdecor/DragResizeInputListener.java  | 288 ++++++++++++++++++
 .../wm/shell/windowdecor/TaskPositioner.java  |  99 ++++++
 .../com/android/server/wm/DisplayContent.java |   4 +-
 .../com/android/server/wm/InputMonitor.java   |   5 +-
 8 files changed, 535 insertions(+), 11 deletions(-)
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeCallback.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
 create mode 100644 libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskPositioner.java

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
index a4d1ce18f32b6..f59e045958b55 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java
@@ -137,11 +137,13 @@ public class WMShellModule {
     @Provides
     static WindowDecorViewModel<?> provideWindowDecorViewModel(
             Context context,
+            @ShellMainThread Handler mainHandler,
             ShellTaskOrganizer taskOrganizer,
             DisplayController displayController,
             SyncTransactionQueue syncQueue) {
         return new CaptionWindowDecorViewModel(
                         context,
+                        mainHandler,
                         taskOrganizer,
                         displayController,
                         syncQueue);
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
index d678f031698e8..6d28d73996f0c 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
@@ -24,6 +24,7 @@ import android.app.ActivityManager;
 import android.app.ActivityManager.RunningTaskInfo;
 import android.app.ActivityTaskManager;
 import android.content.Context;
+import android.os.Handler;
 import android.view.MotionEvent;
 import android.view.SurfaceControl;
 import android.view.View;
@@ -43,15 +44,18 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
     private final ActivityTaskManager mActivityTaskManager;
     private final ShellTaskOrganizer mTaskOrganizer;
     private final Context mContext;
+    private final Handler mMainHandler;
     private final DisplayController mDisplayController;
     private final SyncTransactionQueue mSyncQueue;
 
     public CaptionWindowDecorViewModel(
             Context context,
+            Handler mainHandler,
             ShellTaskOrganizer taskOrganizer,
             DisplayController displayController,
             SyncTransactionQueue syncQueue) {
         mContext = context;
+        mMainHandler = mainHandler;
         mActivityTaskManager = mContext.getSystemService(ActivityTaskManager.class);
         mTaskOrganizer = taskOrganizer;
         mDisplayController = displayController;
@@ -67,9 +71,13 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
                 mTaskOrganizer,
                 taskInfo,
                 taskSurface,
+                mMainHandler,
                 mSyncQueue);
-        CaptionTouchEventListener touchEventListener = new CaptionTouchEventListener(taskInfo);
+        TaskPositioner taskPositioner = new TaskPositioner(mTaskOrganizer, windowDecoration);
+        CaptionTouchEventListener touchEventListener =
+                new CaptionTouchEventListener(taskInfo, taskPositioner);
         windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
+        windowDecoration.setDragResizeCallback(taskPositioner);
         onTaskInfoChanged(taskInfo, windowDecoration);
         return windowDecoration;
     }
@@ -87,10 +95,15 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
 
         private final int mTaskId;
         private final WindowContainerToken mTaskToken;
+        private final DragResizeCallback mDragResizeCallback;
 
-        private CaptionTouchEventListener(RunningTaskInfo taskInfo) {
+        private int mDragPointerId = -1;
+
+        private CaptionTouchEventListener(
+                RunningTaskInfo taskInfo, DragResizeCallback dragResizeCallback) {
             mTaskId = taskInfo.taskId;
             mTaskToken = taskInfo.token;
+            mDragResizeCallback = dragResizeCallback;
         }
 
         @Override
@@ -120,6 +133,8 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
             if (v.getId() != R.id.caption) {
                 return false;
             }
+            handleEventForMove(e);
+
             if (e.getAction() != MotionEvent.ACTION_DOWN) {
                 return false;
             }
@@ -132,5 +147,28 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
             mSyncQueue.queue(wct);
             return true;
         }
+
+        private void handleEventForMove(MotionEvent e) {
+            switch (e.getActionMasked()) {
+                case MotionEvent.ACTION_DOWN:
+                    mDragPointerId  = e.getPointerId(0);
+                    mDragResizeCallback.onDragResizeStart(
+                            0 /* ctrlType */, e.getRawX(0), e.getRawY(0));
+                    break;
+                case MotionEvent.ACTION_MOVE: {
+                    int dragPointerIdx = e.findPointerIndex(mDragPointerId);
+                    mDragResizeCallback.onDragResizeMove(
+                            e.getRawX(dragPointerIdx), e.getRawY(dragPointerIdx));
+                    break;
+                }
+                case MotionEvent.ACTION_UP:
+                case MotionEvent.ACTION_CANCEL: {
+                    int dragPointerIdx = e.findPointerIndex(mDragPointerId);
+                    mDragResizeCallback.onDragResizeEnd(
+                            e.getRawX(dragPointerIdx), e.getRawY(dragPointerIdx));
+                    break;
+                }
+            }
+        }
     }
 }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
index 569be23b9f521..572516d2f8c9b 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
@@ -17,12 +17,14 @@
 package com.android.wm.shell.windowdecor;
 
 import android.app.ActivityManager;
+import android.app.WindowConfiguration;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.graphics.Color;
 import android.graphics.Rect;
 import android.graphics.drawable.GradientDrawable;
 import android.graphics.drawable.VectorDrawable;
+import android.os.Handler;
 import android.view.SurfaceControl;
 import android.view.View;
 import android.window.WindowContainerTransaction;
@@ -48,13 +50,22 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
     // The thickness of shadows of a window that doesn't have focus in DIP.
     private static final int DECOR_SHADOW_UNFOCUSED_THICKNESS_IN_DIP = 5;
 
+    // Height of button (32dp)  + 2 * margin (5dp each)
     private static final int DECOR_CAPTION_HEIGHT_IN_DIP = 42;
-    private static final Rect EMPTY_OUTSET = new Rect();
+    private static final int RESIZE_HANDLE_IN_DIP = 30;
 
+    private static final Rect EMPTY_OUTSET = new Rect();
+    private static final Rect RESIZE_HANDLE_OUTSET = new Rect(
+            RESIZE_HANDLE_IN_DIP, RESIZE_HANDLE_IN_DIP, RESIZE_HANDLE_IN_DIP, RESIZE_HANDLE_IN_DIP);
+
+    private final Handler mHandler;
     private final SyncTransactionQueue mSyncQueue;
 
     private View.OnClickListener mOnCaptionButtonClickListener;
     private View.OnTouchListener mOnCaptionTouchListener;
+    private DragResizeCallback mDragResizeCallback;
+
+    private DragResizeInputListener mDragResizeListener;
 
     private final WindowDecoration.RelayoutResult<WindowDecorLinearLayout> mResult =
             new WindowDecoration.RelayoutResult<>();
@@ -65,9 +76,11 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
             ShellTaskOrganizer taskOrganizer,
             ActivityManager.RunningTaskInfo taskInfo,
             SurfaceControl taskSurface,
+            Handler handler,
             SyncTransactionQueue syncQueue) {
         super(context, displayController, taskOrganizer, taskInfo, taskSurface);
 
+        mHandler = handler;
         mSyncQueue = syncQueue;
     }
 
@@ -78,15 +91,24 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
         mOnCaptionTouchListener = onCaptionTouchListener;
     }
 
+    void setDragResizeCallback(DragResizeCallback dragResizeCallback) {
+        mDragResizeCallback = dragResizeCallback;
+    }
+
     void relayout(ActivityManager.RunningTaskInfo taskInfo) {
         final int shadowRadiusDp = taskInfo.isFocused
                 ? DECOR_SHADOW_FOCUSED_THICKNESS_IN_DIP : DECOR_SHADOW_UNFOCUSED_THICKNESS_IN_DIP;
+        final boolean isFreeform = mTaskInfo.configuration.windowConfiguration.getWindowingMode()
+                == WindowConfiguration.WINDOWING_MODE_FREEFORM;
+        final boolean isDragResizeable = isFreeform && mTaskInfo.isResizeable;
+        final Rect outset = isDragResizeable ? RESIZE_HANDLE_OUTSET : EMPTY_OUTSET;
 
         WindowDecorLinearLayout oldRootView = mResult.mRootView;
+        final SurfaceControl oldDecorationSurface = mDecorationContainerSurface;
         final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
         final WindowContainerTransaction wct = new WindowContainerTransaction();
         relayout(taskInfo, R.layout.caption_window_decoration, oldRootView,
-                DECOR_CAPTION_HEIGHT_IN_DIP, EMPTY_OUTSET, shadowRadiusDp, t, wct, mResult);
+                DECOR_CAPTION_HEIGHT_IN_DIP, outset, shadowRadiusDp, t, wct, mResult);
         taskInfo = null; // Clear it just in case we use it accidentally
 
         mSyncQueue.runInSync(transaction -> {
@@ -97,11 +119,31 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
         });
 
         if (mResult.mRootView == null) {
+            // This means the task is hidden. Nothing is set up in this case including the
+            // decoration surface.
             return;
         }
         if (oldRootView != mResult.mRootView) {
             setupRootView();
         }
+
+        if (!isDragResizeable) {
+            closeDragResizeListener();
+            return;
+        }
+
+        if (oldDecorationSurface != mDecorationContainerSurface) {
+            closeDragResizeListener();
+            mDragResizeListener = new DragResizeInputListener(
+                    mContext,
+                    mHandler,
+                    mDisplay.getDisplayId(),
+                    mDecorationContainerSurface,
+                    mDragResizeCallback);
+        }
+
+        mDragResizeListener.setGeometry(
+                mResult.mWidth, mResult.mHeight, (int) (mResult.mDensity * RESIZE_HANDLE_IN_DIP));
     }
 
     /**
@@ -140,4 +182,18 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
         VectorDrawable closeBackground = (VectorDrawable) close.getBackground();
         closeBackground.setTintList(buttonTintColor);
     }
+
+    private void closeDragResizeListener() {
+        if (mDragResizeListener == null) {
+            return;
+        }
+        mDragResizeListener.close();
+        mDragResizeListener = null;
+    }
+
+    @Override
+    public void close() {
+        closeDragResizeListener();
+        super.close();
+    }
 }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeCallback.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeCallback.java
new file mode 100644
index 0000000000000..ee160a15df198
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeCallback.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+/**
+ * Callback called when receiving drag-resize or drag-move related input events.
+ */
+public interface DragResizeCallback {
+    /**
+     * Called when a drag resize starts.
+     *
+     * @param ctrlType {@link TaskPositioner.CtrlType} indicating the direction of resizing, use
+     *                 {@code 0} to indicate it's a move
+     * @param x x coordinate in window decoration coordinate system where the drag resize starts
+     * @param y y coordinate in window decoration coordinate system where the drag resize starts
+     */
+    void onDragResizeStart(@TaskPositioner.CtrlType int ctrlType, float x, float y);
+
+    /**
+     * Called when the pointer moves during a drag resize.
+     * @param x x coordinate in window decoration coordinate system of the new pointer location
+     * @param y y coordinate in window decoration coordinate system of the new pointer location
+     */
+    void onDragResizeMove(float x, float y);
+
+    /**
+     * Called when a drag resize stops.
+     * @param x x coordinate in window decoration coordinate system where the drag resize stops
+     * @param y y coordinate in window decoration coordinate system where the drag resize stops
+     */
+    void onDragResizeEnd(float x, float y);
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
new file mode 100644
index 0000000000000..c6bbb027c8e65
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
@@ -0,0 +1,288 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import static android.view.WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
+import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_TRUSTED_OVERLAY;
+import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.graphics.Region;
+import android.hardware.input.InputManager;
+import android.os.Binder;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.Looper;
+import android.os.RemoteException;
+import android.view.IWindowSession;
+import android.view.InputChannel;
+import android.view.InputEvent;
+import android.view.InputEventReceiver;
+import android.view.MotionEvent;
+import android.view.PointerIcon;
+import android.view.SurfaceControl;
+import android.view.WindowManagerGlobal;
+
+import com.android.internal.view.BaseIWindow;
+
+/**
+ * An input event listener registered to InputDispatcher to receive input events on task edges and
+ * convert them to drag resize requests.
+ */
+class DragResizeInputListener implements AutoCloseable {
+    private static final String TAG = "DragResizeInputListener";
+
+    private final IWindowSession mWindowSession = WindowManagerGlobal.getWindowSession();
+    private final Handler mHandler;
+    private final InputManager mInputManager;
+
+    private final int mDisplayId;
+    private final BaseIWindow mFakeWindow;
+    private final IBinder mFocusGrantToken;
+    private final SurfaceControl mDecorationSurface;
+    private final InputChannel mInputChannel;
+    private final TaskResizeInputEventReceiver mInputEventReceiver;
+    private final com.android.wm.shell.windowdecor.DragResizeCallback mCallback;
+
+    private int mWidth;
+    private int mHeight;
+    private int mResizeHandleThickness;
+
+    private int mDragPointerId = -1;
+
+    DragResizeInputListener(
+            Context context,
+            Handler handler,
+            int displayId,
+            SurfaceControl decorationSurface,
+            DragResizeCallback callback) {
+        mInputManager = context.getSystemService(InputManager.class);
+        mHandler = handler;
+        mDisplayId = displayId;
+        mDecorationSurface = decorationSurface;
+        // Use a fake window as the backing surface is a container layer and we don't want to create
+        // a buffer layer for it so we can't use ViewRootImpl.
+        mFakeWindow = new BaseIWindow();
+        mFakeWindow.setSession(mWindowSession);
+        mFocusGrantToken = new Binder();
+        mInputChannel = new InputChannel();
+        try {
+            mWindowSession.grantInputChannel(
+                    mDisplayId,
+                    new SurfaceControl(mDecorationSurface, TAG),
+                    mFakeWindow,
+                    null /* hostInputToken */,
+                    FLAG_NOT_FOCUSABLE,
+                    PRIVATE_FLAG_TRUSTED_OVERLAY,
+                    TYPE_APPLICATION,
+                    mFocusGrantToken,
+                    TAG + " of " + decorationSurface.toString(),
+                    mInputChannel);
+        } catch (RemoteException e) {
+            e.rethrowFromSystemServer();
+        }
+
+        mInputEventReceiver = new TaskResizeInputEventReceiver(mInputChannel, mHandler.getLooper());
+        mCallback = callback;
+    }
+
+    /**
+     * Updates geometry of this drag resize handler. Needs to be called every time there is a size
+     * change to notify the input event receiver it's ready to take the next input event. Otherwise
+     * it'll keep batching move events and the drag resize process is stalled.
+     *
+     * This is also used to update the touch regions of this handler every event dispatched here is
+     * a potential resize request.
+     *
+     * @param width The width of the drag resize handler in pixels, including resize handle
+     *              thickness. That is task width + 2 * resize handle thickness.
+     * @param height The height of the drag resize handler in pixels, including resize handle
+     *               thickness. That is task height + 2 * resize handle thickness.
+     * @param resizeHandleThickness The thickness of the resize handle in pixels.
+     */
+    void setGeometry(int width, int height, int resizeHandleThickness) {
+        if (mWidth == width && mHeight == height
+                && mResizeHandleThickness == resizeHandleThickness) {
+            return;
+        }
+
+        mWidth = width;
+        mHeight = height;
+        mResizeHandleThickness = resizeHandleThickness;
+
+        Region touchRegion = new Region();
+        final Rect topInputBounds = new Rect(0, 0, mWidth, mResizeHandleThickness);
+        touchRegion.union(topInputBounds);
+
+        final Rect leftInputBounds = new Rect(0, mResizeHandleThickness,
+                mResizeHandleThickness, mHeight - mResizeHandleThickness);
+        touchRegion.union(leftInputBounds);
+
+        final Rect rightInputBounds = new Rect(
+                mWidth - mResizeHandleThickness, mResizeHandleThickness,
+                mWidth, mHeight - mResizeHandleThickness);
+        touchRegion.union(rightInputBounds);
+
+        final Rect bottomInputBounds = new Rect(0, mHeight - mResizeHandleThickness,
+                mWidth, mHeight);
+        touchRegion.union(bottomInputBounds);
+
+        try {
+            mWindowSession.updateInputChannel(
+                    mInputChannel.getToken(),
+                    mDisplayId,
+                    new SurfaceControl(
+                            mDecorationSurface, "DragResizeInputListener#setTouchRegion"),
+                    FLAG_NOT_FOCUSABLE,
+                    PRIVATE_FLAG_TRUSTED_OVERLAY,
+                    touchRegion);
+        } catch (RemoteException e) {
+            e.rethrowFromSystemServer();
+        }
+
+        // This marks all relevant components have handled the previous resize event and can take
+        // the next one now.
+        mInputEventReceiver.onHandledLastResizeEvent();
+    }
+
+    @Override
+    public void close() {
+        mInputChannel.dispose();
+        try {
+            mWindowSession.remove(mFakeWindow);
+        } catch (RemoteException e) {
+            e.rethrowFromSystemServer();
+        }
+    }
+
+    private class TaskResizeInputEventReceiver extends InputEventReceiver {
+        private boolean mWaitingForLastResizeEventHandled;
+
+        private TaskResizeInputEventReceiver(InputChannel inputChannel, Looper looper) {
+            super(inputChannel, looper);
+        }
+
+        private void onHandledLastResizeEvent() {
+            mWaitingForLastResizeEventHandled = false;
+            consumeBatchedInputEvents(-1);
+        }
+
+        @Override
+        public void onBatchedInputEventPending(int source) {
+            // InputEventReceiver keeps continuous move events in a batched event until explicitly
+            // consuming it or an incompatible event shows up (likely an up event in this case). We
+            // continue to keep move events in the next batched event until we receive a geometry
+            // update so that we don't put too much pressure on the framework with excessive number
+            // of input events if it can't handle them fast enough. It's more responsive to always
+            // resize the task to the latest received coordinates.
+            if (!mWaitingForLastResizeEventHandled) {
+                consumeBatchedInputEvents(-1);
+            }
+        }
+
+        @Override
+        public void onInputEvent(InputEvent inputEvent) {
+            finishInputEvent(inputEvent, handleInputEvent(inputEvent));
+        }
+
+        private boolean handleInputEvent(InputEvent inputEvent) {
+            if (!(inputEvent instanceof MotionEvent)) {
+                return false;
+            }
+
+            MotionEvent e = (MotionEvent) inputEvent;
+            switch (e.getActionMasked()) {
+                case MotionEvent.ACTION_DOWN: {
+                    mDragPointerId = e.getPointerId(0);
+                    mCallback.onDragResizeStart(
+                            calculateCtrlType(e.getX(0), e.getY(0)), e.getRawX(0), e.getRawY(0));
+                    mWaitingForLastResizeEventHandled = false;
+                    break;
+                }
+                case MotionEvent.ACTION_MOVE: {
+                    int dragPointerIndex = e.findPointerIndex(mDragPointerId);
+                    mCallback.onDragResizeMove(
+                            e.getRawX(dragPointerIndex), e.getRawY(dragPointerIndex));
+                    mWaitingForLastResizeEventHandled = true;
+                    break;
+                }
+                case MotionEvent.ACTION_UP:
+                case MotionEvent.ACTION_CANCEL: {
+                    int dragPointerIndex = e.findPointerIndex(mDragPointerId);
+                    mCallback.onDragResizeEnd(
+                            e.getRawX(dragPointerIndex), e.getRawY(dragPointerIndex));
+                    mWaitingForLastResizeEventHandled = false;
+                    mDragPointerId = -1;
+                    break;
+                }
+                case MotionEvent.ACTION_HOVER_ENTER:
+                case MotionEvent.ACTION_HOVER_MOVE: {
+                    updateCursorType(e.getXCursorPosition(), e.getYCursorPosition());
+                    break;
+                }
+                case MotionEvent.ACTION_HOVER_EXIT:
+                    mInputManager.setPointerIconType(PointerIcon.TYPE_DEFAULT);
+                    break;
+            }
+            return true;
+        }
+
+        @TaskPositioner.CtrlType
+        private int calculateCtrlType(float x, float y) {
+            int ctrlType = 0;
+            if (x < mResizeHandleThickness) {
+                ctrlType |= TaskPositioner.CTRL_TYPE_LEFT;
+            }
+            if (x > mWidth - mResizeHandleThickness) {
+                ctrlType |= TaskPositioner.CTRL_TYPE_RIGHT;
+            }
+            if (y < mResizeHandleThickness) {
+                ctrlType |= TaskPositioner.CTRL_TYPE_TOP;
+            }
+            if (y > mHeight - mResizeHandleThickness) {
+                ctrlType |= TaskPositioner.CTRL_TYPE_BOTTOM;
+            }
+            return ctrlType;
+        }
+
+        private void updateCursorType(float x, float y) {
+            @TaskPositioner.CtrlType int ctrlType = calculateCtrlType(x, y);
+
+            int cursorType = PointerIcon.TYPE_DEFAULT;
+            switch (ctrlType) {
+                case TaskPositioner.CTRL_TYPE_LEFT:
+                case TaskPositioner.CTRL_TYPE_RIGHT:
+                    cursorType = PointerIcon.TYPE_HORIZONTAL_DOUBLE_ARROW;
+                    break;
+                case TaskPositioner.CTRL_TYPE_TOP:
+                case TaskPositioner.CTRL_TYPE_BOTTOM:
+                    cursorType = PointerIcon.TYPE_VERTICAL_DOUBLE_ARROW;
+                    break;
+                case TaskPositioner.CTRL_TYPE_LEFT | TaskPositioner.CTRL_TYPE_TOP:
+                case TaskPositioner.CTRL_TYPE_RIGHT | TaskPositioner.CTRL_TYPE_BOTTOM:
+                    cursorType = PointerIcon.TYPE_TOP_LEFT_DIAGONAL_DOUBLE_ARROW;
+                    break;
+                case TaskPositioner.CTRL_TYPE_LEFT | TaskPositioner.CTRL_TYPE_BOTTOM:
+                case TaskPositioner.CTRL_TYPE_RIGHT | TaskPositioner.CTRL_TYPE_TOP:
+                    cursorType = PointerIcon.TYPE_TOP_RIGHT_DIAGONAL_DOUBLE_ARROW;
+                    break;
+            }
+            mInputManager.setPointerIconType(cursorType);
+        }
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskPositioner.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskPositioner.java
new file mode 100644
index 0000000000000..280569b05d870
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/TaskPositioner.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.windowdecor;
+
+import android.annotation.IntDef;
+import android.graphics.PointF;
+import android.graphics.Rect;
+import android.window.WindowContainerTransaction;
+
+import com.android.wm.shell.ShellTaskOrganizer;
+
+class TaskPositioner implements DragResizeCallback {
+
+    @IntDef({CTRL_TYPE_LEFT, CTRL_TYPE_RIGHT, CTRL_TYPE_TOP, CTRL_TYPE_BOTTOM})
+    @interface CtrlType {}
+
+    static final int CTRL_TYPE_LEFT = 1;
+    static final int CTRL_TYPE_RIGHT = 2;
+    static final int CTRL_TYPE_TOP = 4;
+    static final int CTRL_TYPE_BOTTOM = 8;
+
+    private final ShellTaskOrganizer mTaskOrganizer;
+    private final WindowDecoration mWindowDecoration;
+
+    private final Rect mTaskBoundsAtDragStart = new Rect();
+    private final PointF mResizeStartPoint = new PointF();
+    private final Rect mResizeTaskBounds = new Rect();
+
+    private int mCtrlType;
+
+    TaskPositioner(ShellTaskOrganizer taskOrganizer, WindowDecoration windowDecoration) {
+        mTaskOrganizer = taskOrganizer;
+        mWindowDecoration = windowDecoration;
+    }
+
+    @Override
+    public void onDragResizeStart(int ctrlType, float x, float y) {
+        mCtrlType = ctrlType;
+
+        mTaskBoundsAtDragStart.set(
+                mWindowDecoration.mTaskInfo.configuration.windowConfiguration.getBounds());
+        mResizeStartPoint.set(x, y);
+    }
+
+    @Override
+    public void onDragResizeMove(float x, float y) {
+        changeBounds(x, y);
+    }
+
+    @Override
+    public void onDragResizeEnd(float x, float y) {
+        changeBounds(x, y);
+
+        mCtrlType = 0;
+        mTaskBoundsAtDragStart.setEmpty();
+        mResizeStartPoint.set(0, 0);
+    }
+
+    private void changeBounds(float x, float y) {
+        float deltaX = x - mResizeStartPoint.x;
+        mResizeTaskBounds.set(mTaskBoundsAtDragStart);
+        if ((mCtrlType & CTRL_TYPE_LEFT) != 0) {
+            mResizeTaskBounds.left += deltaX;
+        }
+        if ((mCtrlType & CTRL_TYPE_RIGHT) != 0) {
+            mResizeTaskBounds.right += deltaX;
+        }
+        float deltaY = y - mResizeStartPoint.y;
+        if ((mCtrlType & CTRL_TYPE_TOP) != 0) {
+            mResizeTaskBounds.top += deltaY;
+        }
+        if ((mCtrlType & CTRL_TYPE_BOTTOM) != 0) {
+            mResizeTaskBounds.bottom += deltaY;
+        }
+        if (mCtrlType == 0) {
+            mResizeTaskBounds.offset((int) deltaX, (int) deltaY);
+        }
+
+        if (!mResizeTaskBounds.isEmpty()) {
+            final WindowContainerTransaction wct = new WindowContainerTransaction();
+            wct.setBounds(mWindowDecoration.mTaskInfo.token, mResizeTaskBounds);
+            mTaskOrganizer.applyTransaction(wct);
+        }
+    }
+}
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 974340ee2510e..fb1450d0aa61f 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -4880,9 +4880,7 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
                 return true;
             }
 
-            // TODO(b/165794880): Freeform task organizer doesn't support drag-resize yet. Remove
-            // the special case when it does.
-            if (task.isOrganized() && task.getWindowingMode() != WINDOWING_MODE_FREEFORM) {
+            if (task.isOrganized()) {
                 return true;
             }
 
diff --git a/services/core/java/com/android/server/wm/InputMonitor.java b/services/core/java/com/android/server/wm/InputMonitor.java
index 7e06b8823260e..8389dbde3e140 100644
--- a/services/core/java/com/android/server/wm/InputMonitor.java
+++ b/services/core/java/com/android/server/wm/InputMonitor.java
@@ -288,10 +288,7 @@ final class InputMonitor {
         SurfaceControl touchableRegionCrop = null;
         final Task task = w.getTask();
         if (task != null) {
-            // TODO(b/165794636): Remove the special case for freeform window once drag resizing is
-            // handled by WM shell.
-            if (task.isOrganized() && task.getWindowingMode() != WINDOWING_MODE_FULLSCREEN
-                        && !task.inFreeformWindowingMode()) {
+            if (task.isOrganized() && task.getWindowingMode() != WINDOWING_MODE_FULLSCREEN) {
                 // If the window is in a TaskManaged by a TaskOrganizer then most cropping will
                 // be applied using the SurfaceControl hierarchy from the Organizer. This means
                 // we need to make sure that these changes in crop are reflected in the input