Include RootDisplayArea feature id in DisplayAreaInfo

With the RootDisplayArea id, one can create WindowContext with bundle
that specifying the RootDisplayArea using KEY_ROOT_DISPLAY_AREA_ID to
get the WindowContext associated with the DA.

Bug: 176875245
Test: atest WmTests:DisplayAreaTest

core/java/android/window/DisplayAreaInfo.java

@@ -16,6 +16,8 @@
 
 package android.window;
 
+import static android.window.DisplayAreaOrganizer.FEATURE_UNDEFINED;
+
 import android.annotation.NonNull;
 import android.annotation.TestApi;
 import android.content.res.Configuration;
@@ -43,8 +45,17 @@ public final class DisplayAreaInfo implements Parcelable {
      */
     public final int displayId;
 
+    /**
+     * The feature id of this display area.
+     */
     public final int featureId;
 
+    /**
+     * The feature id of the root display area this display area is associated with.
+     * @hide
+     */
+    public int rootDisplayAreaId = FEATURE_UNDEFINED;
+
     public DisplayAreaInfo(@NonNull WindowContainerToken token, int displayId, int featureId) {
         this.token = token;
         this.displayId = displayId;
@@ -56,6 +67,7 @@ public final class DisplayAreaInfo implements Parcelable {
         configuration.readFromParcel(in);
         displayId = in.readInt();
         featureId = in.readInt();
+        rootDisplayAreaId = in.readInt();
     }
 
     @Override
@@ -64,6 +76,7 @@ public final class DisplayAreaInfo implements Parcelable {
         configuration.writeToParcel(dest, flags);
         dest.writeInt(displayId);
         dest.writeInt(featureId);
+        dest.writeInt(rootDisplayAreaId);
     }
 
     @NonNull

core/java/android/window/DisplayAreaOrganizer.java

@@ -33,6 +33,15 @@ import java.util.concurrent.Executor;
 @TestApi
 public class DisplayAreaOrganizer extends WindowOrganizer {
 
+    /**
+     * Key to specify the {@link com.android.server.wm.RootDisplayArea} to attach a window to.
+     * It will be used by the function passed in from
+     * {@link com.android.server.wm.DisplayAreaPolicyBuilder#setSelectRootForWindowFunc(BiFunction)}
+     * to find the Root DA to attach the window.
+     * @hide
+     */
+    public static final String KEY_ROOT_DISPLAY_AREA_ID = "root_display_area_id";
+
     /**
      * The value in display area indicating that no value has been set.
      */

core/java/android/window/WindowContext.java

@@ -57,8 +57,14 @@ public class WindowContext extends ContextWrapper {
      *
      * @param base Base {@link Context} for this new instance.
      * @param type Window type to be used with this context.
-     * @param options A bundle used to pass window-related options.
-     *
+     * @param options A bundle used to pass window-related options. For example, on device with
+     *                multiple DisplayAreaGroups, one may specify the RootDisplayArea for the window
+     *                using {@link DisplayAreaOrganizer#KEY_ROOT_DISPLAY_AREA_ID} in the options.
+     *                Example usage:
+     *                Bundle options = new Bundle();
+     *                options.put(KEY_ROOT_DISPLAY_AREA_ID, displayAreaInfo.rootDisplayAreaId);
+     *                Context windowContext = context.createWindowContext(display, type, options);
+     * @see DisplayAreaInfo#rootDisplayAreaId
      * @hide
      */
     public WindowContext(@NonNull Context base, int type, @Nullable Bundle options) {

services/core/java/com/android/server/wm/DisplayArea.java

@@ -495,8 +495,10 @@ public class DisplayArea<T extends WindowContainer> extends WindowContainer<T> {
 
 
     DisplayAreaInfo getDisplayAreaInfo() {
-        DisplayAreaInfo info = new DisplayAreaInfo(mRemoteToken.toWindowContainerToken(),
+        final DisplayAreaInfo info = new DisplayAreaInfo(mRemoteToken.toWindowContainerToken(),
                 getDisplayContent().getDisplayId(), mFeatureId);
+        final RootDisplayArea root = getRootDisplayArea();
+        info.rootDisplayAreaId = root == null ? getDisplayContent().mFeatureId : root.mFeatureId;
         info.configuration.setTo(getConfiguration());
         return info;
     }

services/core/java/com/android/server/wm/DisplayAreaPolicyBuilder.java

@@ -25,6 +25,7 @@ import static android.view.WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
 import static android.view.WindowManagerPolicyConstants.APPLICATION_LAYER;
 import static android.window.DisplayAreaOrganizer.FEATURE_DEFAULT_TASK_CONTAINER;
 import static android.window.DisplayAreaOrganizer.FEATURE_VENDOR_LAST;
+import static android.window.DisplayAreaOrganizer.KEY_ROOT_DISPLAY_AREA_ID;
 
 import android.annotation.Nullable;
 import android.os.Bundle;
@@ -135,12 +136,6 @@ import java.util.function.BiFunction;
  */
 class DisplayAreaPolicyBuilder {
 
-    /**
-     * Key to specify the {@link RootDisplayArea} to attach the window to. Should be used by the
-     * function passed in from {@link #setSelectRootForWindowFunc(BiFunction)}
-     */
-    static final String KEY_ROOT_DISPLAY_AREA_ID = "root_display_area_id";
-
     @Nullable private HierarchyBuilder mRootHierarchyBuilder;
     private final ArrayList<HierarchyBuilder> mDisplayAreaGroupHierarchyBuilders =
             new ArrayList<>();

services/core/java/com/android/server/wm/ImmersiveModeConfirmation.java

@@ -20,6 +20,7 @@ import static android.app.ActivityManager.LOCK_TASK_MODE_LOCKED;
 import static android.app.ActivityManager.LOCK_TASK_MODE_NONE;
 import static android.view.Display.DEFAULT_DISPLAY;
 import static android.window.DisplayAreaOrganizer.FEATURE_UNDEFINED;
+import static android.window.DisplayAreaOrganizer.KEY_ROOT_DISPLAY_AREA_ID;
 
 import android.animation.ArgbEvaluator;
 import android.animation.ValueAnimator;
@@ -420,7 +421,7 @@ public class ImmersiveModeConfirmation {
         }
 
         final Bundle options = new Bundle();
-        options.putInt(DisplayAreaPolicyBuilder.KEY_ROOT_DISPLAY_AREA_ID, rootDisplayAreaId);
+        options.putInt(KEY_ROOT_DISPLAY_AREA_ID, rootDisplayAreaId);
         return options;
     }
 

services/tests/wmtests/src/com/android/server/wm/DisplayAreaPolicyBuilderTest.java

@@ -35,10 +35,10 @@ import static android.window.DisplayAreaOrganizer.FEATURE_ROOT;
 import static android.window.DisplayAreaOrganizer.FEATURE_VENDOR_FIRST;
 import static android.window.DisplayAreaOrganizer.FEATURE_VENDOR_LAST;
 import static android.window.DisplayAreaOrganizer.FEATURE_WINDOWED_MAGNIFICATION;
+import static android.window.DisplayAreaOrganizer.KEY_ROOT_DISPLAY_AREA_ID;
 
 import static com.android.server.wm.DisplayArea.Type.ABOVE_TASKS;
 import static com.android.server.wm.DisplayAreaPolicyBuilder.Feature;
-import static com.android.server.wm.DisplayAreaPolicyBuilder.KEY_ROOT_DISPLAY_AREA_ID;
 
 import static com.google.common.truth.Truth.assertThat;
 

services/tests/wmtests/src/com/android/server/wm/DisplayAreaTest.java

@@ -61,6 +61,7 @@ import android.platform.test.annotations.Presubmit;
 import android.view.SurfaceControl;
 import android.view.View;
 import android.view.WindowManager;
+import android.window.DisplayAreaInfo;
 import android.window.IDisplayAreaOrganizer;
 
 import com.google.android.collect.Lists;
@@ -566,6 +567,31 @@ public class DisplayAreaTest extends WindowTestsBase {
                 .onDisplayAreaVanished(mockDisplayAreaOrganizer, displayArea);
     }
 
+    @Test
+    public void testGetDisplayAreaInfo() {
+        final DisplayArea<WindowContainer> displayArea = new DisplayArea<>(
+                mWm, BELOW_TASKS, "NewArea", FEATURE_VENDOR_FIRST);
+        mDisplayContent.addChild(displayArea, 0);
+        final DisplayAreaInfo info = displayArea.getDisplayAreaInfo();
+
+        assertThat(info.token).isEqualTo(displayArea.mRemoteToken.toWindowContainerToken());
+        assertThat(info.configuration).isEqualTo(displayArea.getConfiguration());
+        assertThat(info.displayId).isEqualTo(mDisplayContent.getDisplayId());
+        assertThat(info.featureId).isEqualTo(displayArea.mFeatureId);
+        assertThat(info.rootDisplayAreaId).isEqualTo(mDisplayContent.mFeatureId);
+
+        final TaskDisplayArea tda = mDisplayContent.getDefaultTaskDisplayArea();
+        final int tdaIndex = tda.getParent().mChildren.indexOf(tda);
+        final RootDisplayArea root =
+                new DisplayAreaGroup(mWm, "TestRoot", FEATURE_VENDOR_FIRST + 1);
+        mDisplayContent.addChild(root, tdaIndex + 1);
+        displayArea.reparent(root, 0);
+
+        final DisplayAreaInfo info2 = displayArea.getDisplayAreaInfo();
+
+        assertThat(info2.rootDisplayAreaId).isEqualTo(root.mFeatureId);
+    }
+
     private static class TestDisplayArea<T extends WindowContainer> extends DisplayArea<T> {
         private TestDisplayArea(WindowManagerService wms, Rect bounds) {
             super(wms, ANY, "half display area");