Merge "Add FreeformTaskTransitionHandler" into tm-qpr-dev

libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellBaseModule.java

@@ -29,8 +29,6 @@ import com.android.internal.logging.UiEventLogger;
 import com.android.launcher3.icons.IconProvider;
 import com.android.wm.shell.RootDisplayAreaOrganizer;
 import com.android.wm.shell.RootTaskDisplayAreaOrganizer;
-import com.android.wm.shell.sysui.ShellCommandHandler;
-import com.android.wm.shell.sysui.ShellInit;
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.TaskViewFactory;
 import com.android.wm.shell.TaskViewFactoryController;
@@ -59,7 +57,7 @@ import com.android.wm.shell.compatui.CompatUIController;
 import com.android.wm.shell.displayareahelper.DisplayAreaHelper;
 import com.android.wm.shell.displayareahelper.DisplayAreaHelperController;
 import com.android.wm.shell.draganddrop.DragAndDropController;
-import com.android.wm.shell.freeform.FreeformTaskListener;
+import com.android.wm.shell.freeform.FreeformComponents;
 import com.android.wm.shell.fullscreen.FullscreenTaskListener;
 import com.android.wm.shell.hidedisplaycutout.HideDisplayCutoutController;
 import com.android.wm.shell.kidsmode.KidsModeTaskOrganizer;
@@ -78,7 +76,9 @@ import com.android.wm.shell.startingsurface.StartingSurface;
 import com.android.wm.shell.startingsurface.StartingWindowController;
 import com.android.wm.shell.startingsurface.StartingWindowTypeAlgorithm;
 import com.android.wm.shell.startingsurface.phone.PhoneStartingWindowTypeAlgorithm;
+import com.android.wm.shell.sysui.ShellCommandHandler;
 import com.android.wm.shell.sysui.ShellController;
+import com.android.wm.shell.sysui.ShellInit;
 import com.android.wm.shell.sysui.ShellInterface;
 import com.android.wm.shell.transition.ShellTransitions;
 import com.android.wm.shell.transition.Transitions;
@@ -339,15 +339,15 @@ public abstract class WMShellBaseModule {
     // Workaround for dynamic overriding with a default implementation, see {@link DynamicOverride}
     @BindsOptionalOf
     @DynamicOverride
-    abstract FreeformTaskListener<?> optionalFreeformTaskListener();
+    abstract FreeformComponents optionalFreeformComponents();
 
     @WMSingleton
     @Provides
-    static Optional<FreeformTaskListener<?>> provideFreeformTaskListener(
+    static Optional<FreeformComponents> provideFreeformTaskListener(
-            @DynamicOverride Optional<FreeformTaskListener<?>> freeformTaskListener,
+            @DynamicOverride Optional<FreeformComponents> freeformComponents,
             Context context) {
-        if (FreeformTaskListener.isFreeformEnabled(context)) {
+        if (FreeformComponents.isFreeformEnabled(context)) {
-            return freeformTaskListener;
+            return freeformComponents;
         }
         return Optional.empty();
     }
@@ -636,7 +636,7 @@ public abstract class WMShellBaseModule {
             FullscreenTaskListener fullscreenTaskListener,
             Optional<UnfoldAnimationController> unfoldAnimationController,
             Optional<UnfoldTransitionHandler> unfoldTransitionHandler,
-            Optional<FreeformTaskListener<?>> freeformTaskListener,
+            Optional<FreeformComponents> freeformComponents,
             Optional<RecentTasksController> recentTasksOptional,
             Optional<ActivityEmbeddingController> activityEmbeddingOptional,
             Transitions transitions,
@@ -655,7 +655,7 @@ public abstract class WMShellBaseModule {
                 fullscreenTaskListener,
                 unfoldAnimationController,
                 unfoldTransitionHandler,
-                freeformTaskListener,
+                freeformComponents,
                 recentTasksOptional,
                 activityEmbeddingOptional,
                 transitions,

libs/WindowManager/Shell/src/com/android/wm/shell/dagger/WMShellModule.java

@@ -49,7 +49,9 @@ import com.android.wm.shell.common.TransactionPool;
 import com.android.wm.shell.common.annotations.ShellBackgroundThread;
 import com.android.wm.shell.common.annotations.ShellMainThread;
 import com.android.wm.shell.draganddrop.DragAndDropController;
+import com.android.wm.shell.freeform.FreeformComponents;
 import com.android.wm.shell.freeform.FreeformTaskListener;
+import com.android.wm.shell.freeform.FreeformTaskTransitionHandler;
 import com.android.wm.shell.onehanded.OneHandedController;
 import com.android.wm.shell.pip.Pip;
 import com.android.wm.shell.pip.PipAnimationController;
@@ -194,10 +196,27 @@ public abstract class WMShellModule {
     @WMSingleton
     @Provides
     @DynamicOverride
+    static FreeformComponents provideFreeformComponents(
+            FreeformTaskListener<?> taskListener,
+            FreeformTaskTransitionHandler transitionHandler) {
+        return new FreeformComponents(taskListener, Optional.of(transitionHandler));
+    }
+
+    @WMSingleton
+    @Provides
     static FreeformTaskListener<?> provideFreeformTaskListener(
+            WindowDecorViewModel<?> windowDecorViewModel) {
+        return new FreeformTaskListener<>(windowDecorViewModel);
+    }
+
+    @WMSingleton
+    @Provides
+    static FreeformTaskTransitionHandler provideTaskTransitionHandler(
+            Transitions transitions,
             WindowDecorViewModel<?> windowDecorViewModel,
-            SyncTransactionQueue syncQueue) {
+            FreeformTaskListener<?> freeformTaskListener) {
-        return new FreeformTaskListener<>(windowDecorViewModel, syncQueue);
+        return new FreeformTaskTransitionHandler(transitions, windowDecorViewModel,
+                freeformTaskListener);
     }
 
     //

libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformComponents.java

@@ -0,0 +1,56 @@
+/*
+ * 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.freeform;
+
+import static android.content.pm.PackageManager.FEATURE_FREEFORM_WINDOW_MANAGEMENT;
+import static android.provider.Settings.Global.DEVELOPMENT_ENABLE_FREEFORM_WINDOWS_SUPPORT;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import com.android.wm.shell.ShellTaskOrganizer;
+import com.android.wm.shell.transition.Transitions;
+
+import java.util.Optional;
+
+/**
+ * Class that holds freeform related classes. It serves as the single injection point of
+ * all freeform classes to avoid leaking implementation details to the base Dagger module.
+ */
+public class FreeformComponents {
+    public final ShellTaskOrganizer.TaskListener mTaskListener;
+    public final Optional<Transitions.TransitionHandler> mTaskTransitionHandler;
+
+    /**
+     * Creates an instance with the given components.
+     */
+    public FreeformComponents(
+            ShellTaskOrganizer.TaskListener taskListener,
+            Optional<Transitions.TransitionHandler> taskTransitionHandler) {
+        mTaskListener = taskListener;
+        mTaskTransitionHandler = taskTransitionHandler;
+    }
+
+    /**
+     * Returns if this device supports freeform.
+     */
+    public static boolean isFreeformEnabled(Context context) {
+        return context.getPackageManager().hasSystemFeature(FEATURE_FREEFORM_WINDOW_MANAGEMENT)
+                || Settings.Global.getInt(context.getContentResolver(),
+                DEVELOPMENT_ENABLE_FREEFORM_WINDOWS_SUPPORT, 0) != 0;
+    }
+}

libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java

@@ -16,20 +16,18 @@
 
 package com.android.wm.shell.freeform;
 
-import static android.content.pm.PackageManager.FEATURE_FREEFORM_WINDOW_MANAGEMENT;
-import static android.provider.Settings.Global.DEVELOPMENT_ENABLE_FREEFORM_WINDOWS_SUPPORT;
-
 import android.app.ActivityManager.RunningTaskInfo;
-import android.content.Context;
+import android.util.Log;
-import android.provider.Settings;
-import android.util.Slog;
 import android.util.SparseArray;
 import android.view.SurfaceControl;
+import android.window.TransitionInfo;
+
+import androidx.annotation.Nullable;
 
 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.transition.Transitions;
 import com.android.wm.shell.windowdecor.WindowDecorViewModel;
 
 import java.io.PrintWriter;
@@ -45,9 +43,9 @@ public class FreeformTaskListener<T extends AutoCloseable>
     private static final String TAG = "FreeformTaskListener";
 
     private final WindowDecorViewModel<T> mWindowDecorationViewModel;
-    private final SyncTransactionQueue mSyncQueue;
 
     private final SparseArray<State<T>> mTasks = new SparseArray<>();
+    private final SparseArray<T> mWindowDecorOfVanishedTasks = new SparseArray<>();
 
     private static class State<T extends AutoCloseable> {
         RunningTaskInfo mTaskInfo;
@@ -55,58 +53,79 @@ public class FreeformTaskListener<T extends AutoCloseable>
         T mWindowDecoration;
     }
 
-    public FreeformTaskListener(
+    public FreeformTaskListener(WindowDecorViewModel<T> windowDecorationViewModel) {
-            WindowDecorViewModel<T> windowDecorationViewModel,
-            SyncTransactionQueue syncQueue) {
         mWindowDecorationViewModel = windowDecorationViewModel;
-        mSyncQueue = syncQueue;
     }
 
     @Override
     public void onTaskAppeared(RunningTaskInfo taskInfo, SurfaceControl leash) {
-        if (mTasks.get(taskInfo.taskId) != null) {
-            throw new RuntimeException("Task appeared more than once: #" + taskInfo.taskId);
-        }
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Appeared: #%d",
                 taskInfo.taskId);
-        final State<T> state = new State<>();
+        final State<T> state = createOrUpdateTaskState(taskInfo, leash);
+        if (!Transitions.ENABLE_SHELL_TRANSITIONS) {
+            SurfaceControl.Transaction t = new SurfaceControl.Transaction();
+            state.mWindowDecoration =
+                    mWindowDecorationViewModel.createWindowDecoration(taskInfo, leash, t, t);
+            t.apply();
+        }
+    }
+
+    private State<T> createOrUpdateTaskState(RunningTaskInfo taskInfo, SurfaceControl leash) {
+        State<T> state = mTasks.get(taskInfo.taskId);
+        if (state != null) {
+            updateTaskInfo(taskInfo);
+            return state;
+        }
+
+        state = new State<>();
         state.mTaskInfo = taskInfo;
         state.mLeash = leash;
-        state.mWindowDecoration =
-                mWindowDecorationViewModel.createWindowDecoration(taskInfo, leash);
         mTasks.put(taskInfo.taskId, state);
+
+        return state;
     }
 
     @Override
     public void onTaskVanished(RunningTaskInfo taskInfo) {
-        State<T> state = mTasks.get(taskInfo.taskId);
+        final State<T> state = mTasks.get(taskInfo.taskId);
         if (state == null) {
-            Slog.e(TAG, "Task already vanished: #" + taskInfo.taskId);
+            // This is possible if the transition happens before this method.
             return;
         }
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Vanished: #%d",
                 taskInfo.taskId);
         mTasks.remove(taskInfo.taskId);
 
-        try {
+        if (Transitions.ENABLE_SHELL_TRANSITIONS) {
-            state.mWindowDecoration.close();
+            // Save window decorations of closing tasks so that we can hand them over to the
-        } catch (Exception e) {
+            // transition system if this method happens before the transition. In case where the
-            Slog.e(TAG, "Failed to release window decoration.", e);
+            // transition didn't happen, it'd be cleared when the next transition finished.
+            if (state.mWindowDecoration != null) {
+                mWindowDecorOfVanishedTasks.put(taskInfo.taskId, state.mWindowDecoration);
             }
+            return;
+        }
+        releaseWindowDecor(state.mWindowDecoration);
     }
 
     @Override
     public void onTaskInfoChanged(RunningTaskInfo taskInfo) {
-        State<T> state = mTasks.get(taskInfo.taskId);
+        final State<T> state = updateTaskInfo(taskInfo);
-        if (state == null) {
-            throw new RuntimeException(
-                    "Task info changed before appearing: #" + taskInfo.taskId);
-        }
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TASK_ORG, "Freeform Task Info Changed: #%d",
                 taskInfo.taskId);
-        state.mTaskInfo = taskInfo;
+        if (state.mWindowDecoration != null) {
             mWindowDecorationViewModel.onTaskInfoChanged(state.mTaskInfo, state.mWindowDecoration);
         }
+    }
+
+    private State<T> updateTaskInfo(RunningTaskInfo taskInfo) {
+        final State<T> state = mTasks.get(taskInfo.taskId);
+        if (state == null) {
+            throw new RuntimeException("Task info changed before appearing: #" + taskInfo.taskId);
+        }
+        state.mTaskInfo = taskInfo;
+        return state;
+    }
 
     @Override
     public void attachChildSurfaceToTask(int taskId, SurfaceControl.Builder b) {
@@ -126,6 +145,93 @@ public class FreeformTaskListener<T extends AutoCloseable>
         return mTasks.get(taskId).mLeash;
     }
 
+    /**
+     * Creates a window decoration for a transition.
+     *
+     * @param change the change of this task transition that needs to have the task layer as the
+     *               leash
+     * @return {@code true} if it adopts the window decoration; {@code false} otherwise
+     */
+    void createWindowDecoration(
+            TransitionInfo.Change change,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        final State<T> state = createOrUpdateTaskState(change.getTaskInfo(), change.getLeash());
+        state.mWindowDecoration = mWindowDecorationViewModel.createWindowDecoration(
+                state.mTaskInfo, state.mLeash, startT, finishT);
+    }
+
+    /**
+     * Gives out the ownership of the task's window decoration. The given task is leaving (of has
+     * left) this task listener. This is the transition system asking for the ownership.
+     *
+     * @param taskInfo the maximizing task
+     * @return the window decor of the maximizing task if any
+     */
+    T giveWindowDecoration(
+            RunningTaskInfo taskInfo,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        T windowDecor = mWindowDecorOfVanishedTasks.get(taskInfo.taskId);
+        mWindowDecorOfVanishedTasks.remove(taskInfo.taskId);
+        final State<T> state = mTasks.get(taskInfo.taskId);
+        if (state != null) {
+            windowDecor = windowDecor == null ? state.mWindowDecoration : windowDecor;
+            state.mWindowDecoration = null;
+        }
+        mWindowDecorationViewModel.setupWindowDecorationForTransition(
+                taskInfo, startT, finishT, windowDecor);
+        return windowDecor;
+    }
+
+    /**
+     * Adopt the incoming window decoration and lets the window decoration prepare for a transition.
+     *
+     * @param change the change of this task transition that needs to have the task layer as the
+     *               leash
+     * @param startT the start transaction of this transition
+     * @param finishT the finish transaction of this transition
+     * @param windowDecor the window decoration to adopt
+     * @return {@code true} if it adopts the window decoration; {@code false} otherwise
+     */
+    boolean adoptWindowDecoration(
+            TransitionInfo.Change change,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT,
+            @Nullable AutoCloseable windowDecor) {
+        final State<T> state = createOrUpdateTaskState(change.getTaskInfo(), change.getLeash());
+        state.mWindowDecoration = mWindowDecorationViewModel.adoptWindowDecoration(windowDecor);
+        if (state.mWindowDecoration != null) {
+            mWindowDecorationViewModel.setupWindowDecorationForTransition(
+                    state.mTaskInfo, startT, finishT, state.mWindowDecoration);
+            return true;
+        } else {
+            state.mWindowDecoration = mWindowDecorationViewModel.createWindowDecoration(
+                    state.mTaskInfo, state.mLeash, startT, finishT);
+            return false;
+        }
+    }
+
+    void onTaskTransitionFinished() {
+        if (mWindowDecorOfVanishedTasks.size() == 0) {
+            return;
+        }
+        Log.w(TAG, "Clearing window decors of vanished tasks. There could be visual defects "
+                + "if any of them is used later in transitions.");
+        for (int i = 0; i < mWindowDecorOfVanishedTasks.size(); ++i) {
+            releaseWindowDecor(mWindowDecorOfVanishedTasks.valueAt(i));
+        }
+        mWindowDecorOfVanishedTasks.clear();
+    }
+
+    private void releaseWindowDecor(T windowDecor) {
+        try {
+            windowDecor.close();
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to release window decoration.", e);
+        }
+    }
+
     @Override
     public void dump(PrintWriter pw, String prefix) {
         final String innerPrefix = prefix + "  ";
@@ -137,16 +243,4 @@ public class FreeformTaskListener<T extends AutoCloseable>
     public String toString() {
         return TAG;
     }
-
-    /**
-     * Checks if freeform support is enabled in system.
-     *
-     * @param context context used to check settings and package manager.
-     * @return {@code true} if freeform is enabled, {@code false} if not.
-     */
-    public static boolean isFreeformEnabled(Context context) {
-        return context.getPackageManager().hasSystemFeature(FEATURE_FREEFORM_WINDOW_MANAGEMENT)
-                || Settings.Global.getInt(context.getContentResolver(),
-                DEVELOPMENT_ENABLE_FREEFORM_WINDOWS_SUPPORT, 0) != 0;
-    }
 }

libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionHandler.java

@@ -0,0 +1,234 @@
+/*
+ * 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.freeform;
+
+import static android.app.WindowConfiguration.WINDOWING_MODE_FREEFORM;
+import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
+
+import android.app.ActivityManager;
+import android.app.WindowConfiguration;
+import android.os.IBinder;
+import android.util.Log;
+import android.view.SurfaceControl;
+import android.view.WindowManager;
+import android.window.TransitionInfo;
+import android.window.TransitionRequestInfo;
+import android.window.WindowContainerTransaction;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.wm.shell.transition.Transitions;
+import com.android.wm.shell.windowdecor.WindowDecorViewModel;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The {@link Transitions.TransitionHandler} that handles freeform task launches, closes,
+ * maximizing and restoring transitions. It also reports transitions so that window decorations can
+ * be a part of transitions.
+ */
+public class FreeformTaskTransitionHandler
+        implements Transitions.TransitionHandler, FreeformTaskTransitionStarter {
+    private static final String TAG = "FreeformTH";
+
+    private final Transitions mTransitions;
+    private final FreeformTaskListener<?> mFreeformTaskListener;
+
+    private final List<IBinder> mPendingTransitionTokens = new ArrayList<>();
+
+    public FreeformTaskTransitionHandler(
+            Transitions transitions,
+            WindowDecorViewModel<?> windowDecorViewModel,
+            FreeformTaskListener<?> freeformTaskListener) {
+        mTransitions = transitions;
+        mFreeformTaskListener = freeformTaskListener;
+
+        windowDecorViewModel.setFreeformTaskTransitionStarter(this);
+    }
+
+    @Override
+    public void startWindowingModeTransition(
+            int targetWindowingMode, WindowContainerTransaction wct) {
+        final int type;
+        switch (targetWindowingMode) {
+            case WINDOWING_MODE_FULLSCREEN:
+                type = Transitions.TRANSIT_MAXIMIZE;
+                break;
+            case WINDOWING_MODE_FREEFORM:
+                type = Transitions.TRANSIT_RESTORE_FROM_MAXIMIZE;
+                break;
+            default:
+                throw new IllegalArgumentException("Unexpected target windowing mode "
+                        + WindowConfiguration.windowingModeToString(targetWindowingMode));
+        }
+        final IBinder token = mTransitions.startTransition(type, wct, this);
+        mPendingTransitionTokens.add(token);
+    }
+
+    @Override
+    public boolean startAnimation(@NonNull IBinder transition, @NonNull TransitionInfo info,
+            @NonNull SurfaceControl.Transaction startT,
+            @NonNull SurfaceControl.Transaction finishT,
+            @NonNull Transitions.TransitionFinishCallback finishCallback) {
+        boolean transitionHandled = false;
+        final ArrayList<AutoCloseable> windowDecorsInCloseTransitions = new ArrayList<>();
+        for (TransitionInfo.Change change : info.getChanges()) {
+            if ((change.getFlags() & TransitionInfo.FLAG_IS_WALLPAPER) != 0) {
+                continue;
+            }
+
+            final ActivityManager.RunningTaskInfo taskInfo = change.getTaskInfo();
+            if (taskInfo == null || taskInfo.taskId == -1) {
+                continue;
+            }
+
+            switch (change.getMode()) {
+                case WindowManager.TRANSIT_OPEN:
+                    transitionHandled |= startOpenTransition(change, startT, finishT);
+                    break;
+                case WindowManager.TRANSIT_CLOSE:
+                    transitionHandled |= startCloseTransition(
+                            change, windowDecorsInCloseTransitions, startT, finishT);
+                    break;
+                case WindowManager.TRANSIT_CHANGE:
+                    transitionHandled |= startChangeTransition(
+                            transition, info.getType(), change, startT, finishT);
+                    break;
+                case WindowManager.TRANSIT_TO_BACK:
+                case WindowManager.TRANSIT_TO_FRONT:
+                    transitionHandled = true;
+                    break;
+            }
+        }
+
+        mPendingTransitionTokens.remove(transition);
+
+        if (!transitionHandled) {
+            return false;
+        }
+
+        startT.apply();
+        mTransitions.getMainExecutor().execute(
+                () -> finishTransition(windowDecorsInCloseTransitions, finishCallback));
+        return true;
+    }
+
+    private boolean startOpenTransition(
+            TransitionInfo.Change change,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        if (change.getTaskInfo().getWindowingMode() != WINDOWING_MODE_FREEFORM) {
+            return false;
+        }
+        mFreeformTaskListener.createWindowDecoration(change, startT, finishT);
+        return true;
+    }
+
+    private boolean startCloseTransition(
+            TransitionInfo.Change change,
+            ArrayList<AutoCloseable> windowDecors,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        if (change.getTaskInfo().getWindowingMode() != WINDOWING_MODE_FREEFORM) {
+            return false;
+        }
+        final AutoCloseable windowDecor =
+                mFreeformTaskListener.giveWindowDecoration(change.getTaskInfo(), startT, finishT);
+        if (windowDecor != null) {
+            windowDecors.add(windowDecor);
+        }
+
+        return true;
+    }
+
+    private boolean startChangeTransition(
+            IBinder transition,
+            int type,
+            TransitionInfo.Change change,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        AutoCloseable windowDecor = null;
+
+        if (!mPendingTransitionTokens.contains(transition)) {
+            return false;
+        }
+
+        boolean handled = false;
+        final ActivityManager.RunningTaskInfo taskInfo = change.getTaskInfo();
+        if (type == Transitions.TRANSIT_MAXIMIZE
+                && taskInfo.getWindowingMode() == WINDOWING_MODE_FULLSCREEN) {
+            handled = true;
+            windowDecor = mFreeformTaskListener.giveWindowDecoration(
+                    change.getTaskInfo(), startT, finishT);
+            // TODO(b/235638450): Let fullscreen task listener adopt the window decor.
+        }
+
+        if (type == Transitions.TRANSIT_RESTORE_FROM_MAXIMIZE
+                && taskInfo.getWindowingMode() == WINDOWING_MODE_FREEFORM) {
+            handled = true;
+            // TODO(b/235638450): Let fullscreen task listener transfer the window decor.
+            mFreeformTaskListener.adoptWindowDecoration(change, startT, finishT, windowDecor);
+        }
+
+        releaseWindowDecor(windowDecor);
+
+        return handled;
+    }
+
+    private void finishTransition(
+            ArrayList<AutoCloseable> windowDecorsInCloseTransitions,
+            Transitions.TransitionFinishCallback finishCallback) {
+        for (AutoCloseable windowDecor : windowDecorsInCloseTransitions) {
+            releaseWindowDecor(windowDecor);
+        }
+        mFreeformTaskListener.onTaskTransitionFinished();
+        // TODO(b/235638450): Dispatch it to fullscreen task listener.
+        finishCallback.onTransitionFinished(null, null);
+    }
+
+    private void releaseWindowDecor(AutoCloseable windowDecor) {
+        if (windowDecor == null) {
+            return;
+        }
+        try {
+            windowDecor.close();
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to release window decoration.", e);
+        }
+    }
+
+    @Nullable
+    @Override
+    public WindowContainerTransaction handleRequest(@NonNull IBinder transition,
+            @NonNull TransitionRequestInfo request) {
+        final ActivityManager.RunningTaskInfo taskInfo = request.getTriggerTask();
+        if (taskInfo == null || taskInfo.getWindowingMode() != WINDOWING_MODE_FREEFORM) {
+            return null;
+        }
+        switch (request.getType()) {
+            case WindowManager.TRANSIT_OPEN:
+            case WindowManager.TRANSIT_CLOSE:
+            case WindowManager.TRANSIT_TO_FRONT:
+            case WindowManager.TRANSIT_TO_BACK:
+                return new WindowContainerTransaction();
+            default:
+                return null;
+        }
+    }
+}

libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionStarter.java

@@ -0,0 +1,34 @@
+/*
+ * 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.freeform;
+
+import android.window.WindowContainerTransaction;
+
+/**
+ * The interface around {@link FreeformTaskTransitionHandler} for task listeners to start freeform
+ * task transitions.
+ */
+public interface FreeformTaskTransitionStarter {
+
+    /**
+     * Starts a windowing mode transition.
+     *
+     * @param targetWindowingMode the target windowing mode
+     * @param wct the {@link WindowContainerTransaction} that changes the windowing mode
+     */
+    void startWindowingModeTransition(int targetWindowingMode, WindowContainerTransaction wct);
+}

libs/WindowManager/Shell/src/com/android/wm/shell/sysui/ShellInit.java

@@ -34,7 +34,7 @@ import com.android.wm.shell.common.DisplayImeController;
 import com.android.wm.shell.common.DisplayInsetsController;
 import com.android.wm.shell.common.ShellExecutor;
 import com.android.wm.shell.draganddrop.DragAndDropController;
-import com.android.wm.shell.freeform.FreeformTaskListener;
+import com.android.wm.shell.freeform.FreeformComponents;
 import com.android.wm.shell.fullscreen.FullscreenTaskListener;
 import com.android.wm.shell.kidsmode.KidsModeTaskOrganizer;
 import com.android.wm.shell.pip.phone.PipTouchHandler;
@@ -68,7 +68,7 @@ public class ShellInit {
     private final FullscreenTaskListener mFullscreenTaskListener;
     private final Optional<UnfoldAnimationController> mUnfoldController;
     private final Optional<UnfoldTransitionHandler> mUnfoldTransitionHandler;
-    private final Optional<FreeformTaskListener<?>> mFreeformTaskListenerOptional;
+    private final Optional<FreeformComponents> mFreeformComponentsOptional;
     private final ShellExecutor mMainExecutor;
     private final Transitions mTransitions;
     private final StartingWindowController mStartingWindow;
@@ -93,7 +93,7 @@ public class ShellInit {
             FullscreenTaskListener fullscreenTaskListener,
             Optional<UnfoldAnimationController> unfoldAnimationController,
             Optional<UnfoldTransitionHandler> unfoldTransitionHandler,
-            Optional<FreeformTaskListener<?>> freeformTaskListenerOptional,
+            Optional<FreeformComponents> freeformComponentsOptional,
             Optional<RecentTasksController> recentTasks,
             Optional<ActivityEmbeddingController> activityEmbeddingOptional,
             Transitions transitions,
@@ -111,7 +111,7 @@ public class ShellInit {
         mPipTouchHandlerOptional = pipTouchHandlerOptional;
         mUnfoldController = unfoldAnimationController;
         mUnfoldTransitionHandler = unfoldTransitionHandler;
-        mFreeformTaskListenerOptional = freeformTaskListenerOptional;
+        mFreeformComponentsOptional = freeformComponentsOptional;
         mRecentTasks = recentTasks;
         mActivityEmbeddingOptional = activityEmbeddingOptional;
         mTransitions = transitions;
@@ -143,6 +143,8 @@ public class ShellInit {
             mTransitions.register(mShellTaskOrganizer);
             mActivityEmbeddingOptional.ifPresent(ActivityEmbeddingController::init);
             mUnfoldTransitionHandler.ifPresent(UnfoldTransitionHandler::init);
+            mFreeformComponentsOptional.flatMap(f -> f.mTaskTransitionHandler)
+                    .ifPresent(mTransitions::addHandler);
             if (mSplitScreenOptional.isPresent() && mPipTouchHandlerOptional.isPresent()) {
                 final DefaultMixedHandler mixedHandler = new DefaultMixedHandler(mTransitions,
                         mPipTouchHandlerOptional.get().getTransitionHandler(),
@@ -158,9 +160,9 @@ public class ShellInit {
         mPipTouchHandlerOptional.ifPresent((handler) -> handler.init());
 
         // Initialize optional freeform
-        mFreeformTaskListenerOptional.ifPresent(f ->
+        mFreeformComponentsOptional.ifPresent(f ->
                 mShellTaskOrganizer.addListenerForType(
-                        f, ShellTaskOrganizer.TASK_LISTENER_TYPE_FREEFORM));
+                        f.mTaskListener, ShellTaskOrganizer.TASK_LISTENER_TYPE_FREEFORM));
 
         mUnfoldController.ifPresent(UnfoldAnimationController::init);
         mRecentTasks.ifPresent(RecentTasksController::init);

libs/WindowManager/Shell/src/com/android/wm/shell/transition/Transitions.java

@@ -98,6 +98,12 @@ public class Transitions implements RemoteCallable<Transitions> {
     /** Transition type for dismissing split-screen. */
     public static final int TRANSIT_SPLIT_DISMISS = TRANSIT_FIRST_CUSTOM + 7;
 
+    /** Transition type for freeform to maximize transition. */
+    public static final int TRANSIT_MAXIMIZE = WindowManager.TRANSIT_FIRST_CUSTOM + 8;
+
+    /** Transition type for maximize to freeform transition. */
+    public static final int TRANSIT_RESTORE_FROM_MAXIMIZE = WindowManager.TRANSIT_FIRST_CUSTOM + 9;
+
     private final WindowOrganizer mOrganizer;
     private final Context mContext;
     private final ShellExecutor mMainExecutor;

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java

@@ -36,6 +36,8 @@ 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;
+import com.android.wm.shell.freeform.FreeformTaskTransitionStarter;
+import com.android.wm.shell.transition.Transitions;
 
 /**
  * View model for the window decoration with a caption and shadows. Works with
@@ -50,6 +52,8 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
     private final DisplayController mDisplayController;
     private final SyncTransactionQueue mSyncQueue;
 
+    private FreeformTaskTransitionStarter mTransitionStarter;
+
     public CaptionWindowDecorViewModel(
             Context context,
             Handler mainHandler,
@@ -66,9 +70,17 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
         mSyncQueue = syncQueue;
     }
 
+    @Override
+    public void setFreeformTaskTransitionStarter(FreeformTaskTransitionStarter transitionStarter) {
+        mTransitionStarter = transitionStarter;
+    }
+
     @Override
     public CaptionWindowDecoration createWindowDecoration(
-            ActivityManager.RunningTaskInfo taskInfo, SurfaceControl taskSurface) {
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
         final CaptionWindowDecoration windowDecoration = new CaptionWindowDecoration(
                 mContext,
                 mDisplayController,
@@ -83,18 +95,39 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
                 new CaptionTouchEventListener(taskInfo, taskPositioner);
         windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
         windowDecoration.setDragResizeCallback(taskPositioner);
-        onTaskInfoChanged(taskInfo, windowDecoration);
+        setupWindowDecorationForTransition(taskInfo, startT, finishT, windowDecoration);
+        setupCaptionColor(taskInfo, windowDecoration);
         return windowDecoration;
     }
 
+    @Override
+    public CaptionWindowDecoration adoptWindowDecoration(AutoCloseable windowDecor) {
+        return (windowDecor instanceof CaptionWindowDecoration)
+                ? (CaptionWindowDecoration) windowDecor
+                : null;
+    }
+
     @Override
     public void onTaskInfoChanged(RunningTaskInfo taskInfo, CaptionWindowDecoration decoration) {
         decoration.relayout(taskInfo);
 
+        setupCaptionColor(taskInfo, decoration);
+    }
+
+    private void setupCaptionColor(RunningTaskInfo taskInfo, CaptionWindowDecoration decoration) {
         int statusBarColor = taskInfo.taskDescription.getStatusBarColor();
         decoration.setCaptionColor(statusBarColor);
     }
 
+    @Override
+    public void setupWindowDecorationForTransition(
+            RunningTaskInfo taskInfo,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT,
+            CaptionWindowDecoration decoration) {
+        decoration.relayout(taskInfo, startT, finishT);
+    }
+
     private class CaptionTouchEventListener implements
             View.OnClickListener, View.OnTouchListener {
 
@@ -105,7 +138,8 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
         private int mDragPointerId = -1;
 
         private CaptionTouchEventListener(
-                RunningTaskInfo taskInfo, DragResizeCallback dragResizeCallback) {
+                RunningTaskInfo taskInfo,
+                DragResizeCallback dragResizeCallback) {
             mTaskId = taskInfo.taskId;
             mTaskToken = taskInfo.token;
             mDragResizeCallback = dragResizeCallback;
@@ -113,7 +147,7 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
 
         @Override
         public void onClick(View v) {
-            int id = v.getId();
+            final int id = v.getId();
             if (id == R.id.close_window) {
                 mActivityTaskManager.removeTask(mTaskId);
             } else if (id == R.id.maximize_window) {
@@ -129,9 +163,13 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
                 if (targetWindowingMode == WINDOWING_MODE_FULLSCREEN) {
                     wct.setBounds(mTaskToken, null);
                 }
+                if (Transitions.ENABLE_SHELL_TRANSITIONS) {
+                    mTransitionStarter.startWindowingModeTransition(targetWindowingMode, wct);
+                } else {
                     mSyncQueue.queue(wct);
                 }
             }
+        }
 
         @Override
         public boolean onTouch(View v, MotionEvent e) {

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java

@@ -101,6 +101,16 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
     @Override
     void relayout(ActivityManager.RunningTaskInfo taskInfo) {
+        final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
+        relayout(taskInfo, t, t);
+        mSyncQueue.runInSync(transaction -> {
+            transaction.merge(t);
+            t.close();
+        });
+    }
+
+    void relayout(ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl.Transaction startT, SurfaceControl.Transaction finishT) {
         final int shadowRadiusDp = taskInfo.isFocused
                 ? DECOR_SHADOW_FOCUSED_THICKNESS_IN_DIP : DECOR_SHADOW_UNFOCUSED_THICKNESS_IN_DIP;
         final boolean isFreeform = mTaskInfo.configuration.windowConfiguration.getWindowingMode()
@@ -110,18 +120,12 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
         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, outset, shadowRadiusDp, t, wct, mResult);
+                DECOR_CAPTION_HEIGHT_IN_DIP, outset, shadowRadiusDp, startT, finishT, 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) {
             // This means something blocks the window decor from showing, e.g. the task is hidden.

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java

@@ -19,6 +19,10 @@ package com.android.wm.shell.windowdecor;
 import android.app.ActivityManager;
 import android.view.SurfaceControl;
 
+import androidx.annotation.Nullable;
+
+import com.android.wm.shell.freeform.FreeformTaskTransitionStarter;
+
 /**
  * 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
@@ -29,14 +33,35 @@ import android.view.SurfaceControl;
  */
 public interface WindowDecorViewModel<T extends AutoCloseable> {
 
+    /**
+     * Sets the transition starter that starts freeform task transitions.
+     *
+     * @param transitionStarter the transition starter that starts freeform task transitions
+     */
+    void setFreeformTaskTransitionStarter(FreeformTaskTransitionStarter transitionStarter);
+
     /**
      * Creates a window decoration for the given task.
      *
      * @param taskInfo the initial task info of the task
      * @param taskSurface the surface of the task
+     * @param startT the start transaction to be applied before the transition
+     * @param finishT the finish transaction to restore states after the transition
      * @return the window decoration object
      */
-    T createWindowDecoration(ActivityManager.RunningTaskInfo taskInfo, SurfaceControl taskSurface);
+    T createWindowDecoration(
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT);
+
+    /**
+     * Adopts the window decoration if possible.
+     *
+     * @param windowDecor the potential window decoration to adopt
+     * @return the window decoration if it can be adopted, or {@code null} otherwise.
+     */
+    T adoptWindowDecoration(@Nullable AutoCloseable windowDecor);
 
     /**
      * Notifies a task info update on the given task, with the window decoration created previously
@@ -46,4 +71,18 @@ public interface WindowDecorViewModel<T extends AutoCloseable> {
      * @param windowDecoration the window decoration created for the task
      */
     void onTaskInfoChanged(ActivityManager.RunningTaskInfo taskInfo, T windowDecoration);
+
+    /**
+     * Notifies a transition is about to start about the given task to give the window decoration a
+     * chance to prepare for this transition.
+     *
+     * @param startT the start transaction to be applied before the transition
+     * @param finishT the finish transaction to restore states after the transition
+     * @param windowDecoration the window decoration created for the task
+     */
+    void setupWindowDecorationForTransition(
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT,
+            T windowDecoration);
 }

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java

@@ -140,8 +140,9 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
     abstract void relayout(RunningTaskInfo taskInfo);
 
     void relayout(RunningTaskInfo taskInfo, int layoutResId, T rootView, float captionHeightDp,
-            Rect outsetsDp, float shadowRadiusDp, SurfaceControl.Transaction t,
+            Rect outsetsDp, float shadowRadiusDp, SurfaceControl.Transaction startT,
-            WindowContainerTransaction wct, RelayoutResult<T> outResult) {
+            SurfaceControl.Transaction finishT, WindowContainerTransaction wct,
+            RelayoutResult<T> outResult) {
         outResult.reset();
 
         final Configuration oldTaskConfig = mTaskInfo.getConfiguration();
@@ -151,7 +152,7 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
 
         if (!mTaskInfo.isVisible) {
             releaseViews();
-            t.hide(mTaskSurface);
+            finishT.hide(mTaskSurface);
             return;
         }
 
@@ -192,7 +193,7 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
                     .setParent(mTaskSurface)
                     .build();
 
-            t.setTrustedOverlay(mDecorationContainerSurface, true);
+            startT.setTrustedOverlay(mDecorationContainerSurface, true);
         }
 
         final Rect taskBounds = taskConfig.windowConfiguration.getBounds();
@@ -205,7 +206,8 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
         outResult.mHeight = taskBounds.height()
                 + (int) (outsetsDp.bottom * outResult.mDensity)
                 - decorContainerOffsetY;
-        t.setPosition(mDecorationContainerSurface, decorContainerOffsetX, decorContainerOffsetY)
+        startT.setPosition(
+                        mDecorationContainerSurface, decorContainerOffsetX, decorContainerOffsetY)
                 .setWindowCrop(mDecorationContainerSurface, outResult.mWidth, outResult.mHeight)
                 .setLayer(mDecorationContainerSurface, mTaskInfo.numActivities + 1)
                 .show(mDecorationContainerSurface);
@@ -225,7 +227,7 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
         mTmpColor[0] = (float) Color.red(backgroundColorInt) / 255.f;
         mTmpColor[1] = (float) Color.green(backgroundColorInt) / 255.f;
         mTmpColor[2] = (float) Color.blue(backgroundColorInt) / 255.f;
-        t.setWindowCrop(mTaskBackgroundSurface, taskBounds.width(), taskBounds.height())
+        startT.setWindowCrop(mTaskBackgroundSurface, taskBounds.width(), taskBounds.height())
                 .setShadowRadius(mTaskBackgroundSurface, shadowRadius)
                 .setColor(mTaskBackgroundSurface, mTmpColor);
 
@@ -264,9 +266,9 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
                 decorContainerOffsetY,
                 outResult.mWidth + decorContainerOffsetX,
                 outResult.mHeight + decorContainerOffsetY);
-        t.setPosition(mTaskSurface, taskPosition.x, taskPosition.y)
+        startT.show(mTaskSurface);
-                .setCrop(mTaskSurface, mTaskSurfaceCrop)
+        finishT.setPosition(mTaskSurface, taskPosition.x, taskPosition.y)
-                .show(mTaskSurface);
+                .setCrop(mTaskSurface, mTaskSurfaceCrop);
     }
 
     /**

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/ShellInitTest.java

@@ -31,7 +31,7 @@ import com.android.wm.shell.common.DisplayImeController;
 import com.android.wm.shell.common.DisplayInsetsController;
 import com.android.wm.shell.common.ShellExecutor;
 import com.android.wm.shell.draganddrop.DragAndDropController;
-import com.android.wm.shell.freeform.FreeformTaskListener;
+import com.android.wm.shell.freeform.FreeformComponents;
 import com.android.wm.shell.fullscreen.FullscreenTaskListener;
 import com.android.wm.shell.kidsmode.KidsModeTaskOrganizer;
 import com.android.wm.shell.pip.phone.PipTouchHandler;
@@ -71,7 +71,7 @@ public class ShellInitTest extends ShellTestCase {
     @Mock private FullscreenTaskListener mFullscreenTaskListener;
     @Mock private Optional<UnfoldAnimationController> mUnfoldAnimationController;
     @Mock private Optional<UnfoldTransitionHandler> mUnfoldTransitionHandler;
-    @Mock private Optional<FreeformTaskListener<?>> mFreeformTaskListenerOptional;
+    @Mock private Optional<FreeformComponents> mFreeformComponentsOptional;
     @Mock private Optional<RecentTasksController> mRecentTasks;
     @Mock private Optional<ActivityEmbeddingController> mActivityEmbeddingController;
     @Mock private Transitions mTransitions;
@@ -87,7 +87,7 @@ public class ShellInitTest extends ShellTestCase {
                 mDisplayInsetsController, mDragAndDropController, mShellTaskOrganizer,
                 mKidsModeTaskOrganizer, mBubblesOptional, mSplitScreenOptional,
                 mPipTouchHandlerOptional, mFullscreenTaskListener, mUnfoldAnimationController,
-                mUnfoldTransitionHandler, mFreeformTaskListenerOptional, mRecentTasks,
+                mUnfoldTransitionHandler, mFreeformComponentsOptional, mRecentTasks,
                 mActivityEmbeddingController, mTransitions, mStartingWindow, mMainExecutor);
     }
 

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/WindowDecorationTests.java

@@ -98,11 +98,13 @@ public class WindowDecorationTests extends ShellTestCase {
     private WindowContainerTransaction mMockWindowContainerTransaction;
 
     private final List<SurfaceControl.Builder> mMockSurfaceControlBuilders = new ArrayList<>();
-    private SurfaceControl.Transaction mMockSurfaceControlTransaction;
+    private SurfaceControl.Transaction mMockSurfaceControlStartT;
+    private SurfaceControl.Transaction mMockSurfaceControlFinishT;
 
     @Before
     public void setUp() {
-        mMockSurfaceControlTransaction = createMockSurfaceControlTransaction();
+        mMockSurfaceControlStartT = createMockSurfaceControlTransaction();
+        mMockSurfaceControlFinishT = createMockSurfaceControlTransaction();
 
         doReturn(mMockSurfaceControlViewHost).when(mMockSurfaceControlViewHostFactory)
                 .create(any(), any(), any(), anyBoolean());
@@ -149,7 +151,7 @@ public class WindowDecorationTests extends ShellTestCase {
         verify(mMockSurfaceControlViewHostFactory, never())
                 .create(any(), any(), any(), anyBoolean());
 
-        verify(mMockSurfaceControlTransaction).hide(taskSurface);
+        verify(mMockSurfaceControlFinishT).hide(taskSurface);
 
         assertNull(mRelayoutResult.mRootView);
     }
@@ -192,16 +194,16 @@ public class WindowDecorationTests extends ShellTestCase {
 
         verify(decorContainerSurfaceBuilder).setParent(taskSurface);
         verify(decorContainerSurfaceBuilder).setContainerLayer();
-        verify(mMockSurfaceControlTransaction).setTrustedOverlay(decorContainerSurface, true);
+        verify(mMockSurfaceControlStartT).setTrustedOverlay(decorContainerSurface, true);
-        verify(mMockSurfaceControlTransaction).setPosition(decorContainerSurface, -20, -40);
+        verify(mMockSurfaceControlStartT).setPosition(decorContainerSurface, -20, -40);
-        verify(mMockSurfaceControlTransaction).setWindowCrop(decorContainerSurface, 380, 220);
+        verify(mMockSurfaceControlStartT).setWindowCrop(decorContainerSurface, 380, 220);
 
         verify(taskBackgroundSurfaceBuilder).setParent(taskSurface);
         verify(taskBackgroundSurfaceBuilder).setEffectLayer();
-        verify(mMockSurfaceControlTransaction).setWindowCrop(taskBackgroundSurface, 300, 100);
+        verify(mMockSurfaceControlStartT).setWindowCrop(taskBackgroundSurface, 300, 100);
-        verify(mMockSurfaceControlTransaction)
+        verify(mMockSurfaceControlStartT)
                 .setColor(taskBackgroundSurface, new float[] {1.f, 1.f, 0.f});
-        verify(mMockSurfaceControlTransaction).setShadowRadius(taskBackgroundSurface, 10);
+        verify(mMockSurfaceControlStartT).setShadowRadius(taskBackgroundSurface, 10);
 
         verify(mMockSurfaceControlViewHostFactory)
                 .create(any(), eq(defaultDisplay), any(), anyBoolean());
@@ -218,11 +220,11 @@ public class WindowDecorationTests extends ShellTestCase {
                             new int[] { InsetsState.ITYPE_CAPTION_BAR });
         }
 
-        verify(mMockSurfaceControlTransaction)
+        verify(mMockSurfaceControlFinishT)
                 .setPosition(taskSurface, TASK_POSITION_IN_PARENT.x, TASK_POSITION_IN_PARENT.y);
-        verify(mMockSurfaceControlTransaction)
+        verify(mMockSurfaceControlFinishT)
                 .setCrop(taskSurface, new Rect(-20, -40, 360, 180));
-        verify(mMockSurfaceControlTransaction)
+        verify(mMockSurfaceControlStartT)
                 .show(taskSurface);
 
         assertEquals(380, mRelayoutResult.mWidth);
@@ -319,8 +321,8 @@ public class WindowDecorationTests extends ShellTestCase {
         @Override
         void relayout(ActivityManager.RunningTaskInfo taskInfo) {
             relayout(null /* taskInfo */, 0 /* layoutResId */, mMockView, CAPTION_HEIGHT_DP,
-                    mOutsetsDp, SHADOW_RADIUS_DP, mMockSurfaceControlTransaction,
+                    mOutsetsDp, SHADOW_RADIUS_DP, mMockSurfaceControlStartT,
-                    mMockWindowContainerTransaction, mRelayoutResult);
+                    mMockSurfaceControlFinishT, mMockWindowContainerTransaction, mRelayoutResult);
         }
     }
 }