diff --git a/api/test-current.txt b/api/test-current.txt
index 6ab60d908c64c..fda0a8608c7b3 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -5215,10 +5215,10 @@ package android.window {
     method public void onDisplayAreaAppeared(@NonNull android.window.WindowContainerToken);
     method public void onDisplayAreaVanished(@NonNull android.window.WindowContainerToken);
     method @RequiresPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS) public void registerOrganizer(int);
+    field public static final int FEATURE_DEFAULT_TASK_CONTAINER = 1; // 0x1
     field public static final int FEATURE_ROOT = 0; // 0x0
     field public static final int FEATURE_SYSTEM_FIRST = 0; // 0x0
     field public static final int FEATURE_SYSTEM_LAST = 10000; // 0x2710
-    field public static final int FEATURE_TASK_CONTAINER = 1; // 0x1
     field public static final int FEATURE_UNDEFINED = -1; // 0xffffffff
     field public static final int FEATURE_VENDOR_FIRST = 10001; // 0x2711
     field public static final int FEATURE_WINDOW_TOKENS = 2; // 0x2
diff --git a/core/java/android/window/DisplayAreaOrganizer.java b/core/java/android/window/DisplayAreaOrganizer.java
index eee222b9bf4c0..6ae70b7799605 100644
--- a/core/java/android/window/DisplayAreaOrganizer.java
+++ b/core/java/android/window/DisplayAreaOrganizer.java
@@ -33,8 +33,8 @@ public class DisplayAreaOrganizer extends WindowOrganizer {
     public static final int FEATURE_SYSTEM_FIRST = 0;
     // The Root display area on a display
     public static final int FEATURE_ROOT = FEATURE_SYSTEM_FIRST;
-    // Display area hosting the task container.
-    public static final int FEATURE_TASK_CONTAINER = FEATURE_SYSTEM_FIRST + 1;
+    // Display area hosting the default task container.
+    public static final int FEATURE_DEFAULT_TASK_CONTAINER = FEATURE_SYSTEM_FIRST + 1;
     // Display area hosting non-activity window tokens.
     public static final int FEATURE_WINDOW_TOKENS = FEATURE_SYSTEM_FIRST + 2;
 
diff --git a/services/core/java/com/android/server/wm/ActivityStackSupervisor.java b/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
index 1e5a924e1d4d2..0470ffa6cdcae 100644
--- a/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
@@ -1469,7 +1469,7 @@ public class ActivityStackSupervisor implements RecentTasks.Callbacks {
             if (toDisplay.getDisplayId() != stack.getDisplayId()) {
                 stack.reparent(toDisplay.getDefaultTaskDisplayArea(), false /* onTop */);
             } else {
-                toDisplay.mTaskContainers.positionStackAtBottom(stack);
+                toDisplay.getDefaultTaskDisplayArea().positionStackAtBottom(stack);
             }
 
             mRootWindowContainer.ensureActivitiesVisible(null, 0, PRESERVE_WINDOWS);
diff --git a/services/core/java/com/android/server/wm/DisplayArea.java b/services/core/java/com/android/server/wm/DisplayArea.java
index edd14b7bebf37..a512337c96ecb 100644
--- a/services/core/java/com/android/server/wm/DisplayArea.java
+++ b/services/core/java/com/android/server/wm/DisplayArea.java
@@ -54,7 +54,6 @@ import java.util.function.Predicate;
  * - BELOW_TASKS: Can only contain BELOW_TASK DisplayAreas and WindowTokens that go below tasks.
  * - ABOVE_TASKS: Can only contain ABOVE_TASK DisplayAreas and WindowTokens that go above tasks.
  * - ANY: Can contain any kind of DisplayArea, and any kind of WindowToken or the Task container.
- *        Cannot have a sibling that is of type ANY.
  *
  * @param <T> type of the children of the DisplayArea.
  */
@@ -274,7 +273,6 @@ public class DisplayArea<T extends WindowContainer> extends WindowContainer<T> {
         ANY;
 
         static void checkSiblings(Type bottom, Type top) {
-            checkState(!(bottom == ANY && top == ANY), "ANY cannot be a sibling of ANY");
             checkState(!(bottom != BELOW_TASKS && top == BELOW_TASKS),
                     bottom + " must be above BELOW_TASKS");
             checkState(!(bottom == ABOVE_TASKS && top != ABOVE_TASKS),
diff --git a/services/core/java/com/android/server/wm/DisplayAreaPolicy.java b/services/core/java/com/android/server/wm/DisplayAreaPolicy.java
index 9821573362956..15b6f9735bf17 100644
--- a/services/core/java/com/android/server/wm/DisplayAreaPolicy.java
+++ b/services/core/java/com/android/server/wm/DisplayAreaPolicy.java
@@ -16,9 +16,14 @@
 
 package com.android.server.wm;
 
+import static android.window.DisplayAreaOrganizer.FEATURE_DEFAULT_TASK_CONTAINER;
+
 import android.content.res.Resources;
 import android.text.TextUtils;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Policy that manages DisplayAreas.
  */
@@ -37,9 +42,9 @@ public abstract class DisplayAreaPolicy {
     protected final DisplayArea<? extends WindowContainer> mImeContainer;
 
     /**
-     * The Tasks container. Tasks etc. are automatically added to this container.
+     * The task display areas. Tasks etc. are automatically added to these containers.
      */
-    protected final DisplayArea<? extends ActivityStack> mTaskContainers;
+    protected final List<TaskDisplayArea> mTaskDisplayAreas;
 
     /**
      * Construct a new {@link DisplayAreaPolicy}
@@ -48,19 +53,19 @@ public abstract class DisplayAreaPolicy {
      * @param content the display content for which the policy applies
      * @param root the root display area under which the policy operates
      * @param imeContainer the ime container that the policy must attach
-     * @param taskDisplayArea the task container that the policy must attach
+     * @param taskDisplayAreas the task display areas that the policy must attach
      *
      * @see #attachDisplayAreas()
      */
     protected DisplayAreaPolicy(WindowManagerService wmService,
             DisplayContent content, DisplayArea.Root root,
             DisplayArea<? extends WindowContainer> imeContainer,
-            DisplayArea<? extends ActivityStack> taskDisplayArea) {
+            List<TaskDisplayArea> taskDisplayAreas) {
         mWmService = wmService;
         mContent = content;
         mRoot = root;
         mImeContainer = imeContainer;
-        mTaskContainers = taskDisplayArea;
+        mTaskDisplayAreas = taskDisplayAreas;
     }
 
     /**
@@ -80,15 +85,32 @@ public abstract class DisplayAreaPolicy {
      */
     public abstract void addWindow(WindowToken token);
 
+    /**
+     * @return the number of task display areas on the display.
+     */
+    public int getTaskDisplayAreaCount() {
+        return mTaskDisplayAreas.size();
+    }
+
+    /**
+     * @return the task display area at index.
+     */
+    public TaskDisplayArea getTaskDisplayAreaAt(int index) {
+        return mTaskDisplayAreas.get(index);
+    }
+
     /** Provider for platform-default display area policy. */
     static final class DefaultProvider implements DisplayAreaPolicy.Provider {
         @Override
         public DisplayAreaPolicy instantiate(WindowManagerService wmService,
                 DisplayContent content, DisplayArea.Root root,
-                DisplayArea<? extends WindowContainer> imeContainer,
-                TaskDisplayArea taskDisplayArea) {
+                DisplayArea<? extends WindowContainer> imeContainer) {
+            final TaskDisplayArea defaultTaskDisplayArea = new TaskDisplayArea(content, wmService,
+                    "DefaultTaskDisplayArea", FEATURE_DEFAULT_TASK_CONTAINER);
+            final List<TaskDisplayArea> tdaList = new ArrayList<>();
+            tdaList.add(defaultTaskDisplayArea);
             return new DisplayAreaPolicyBuilder()
-                    .build(wmService, content, root, imeContainer, taskDisplayArea);
+                    .build(wmService, content, root, imeContainer, tdaList);
         }
     }
 
@@ -107,8 +129,7 @@ public abstract class DisplayAreaPolicy {
          */
         DisplayAreaPolicy instantiate(WindowManagerService wmService,
                 DisplayContent content, DisplayArea.Root root,
-                DisplayArea<? extends WindowContainer> imeContainer,
-                TaskDisplayArea taskDisplayArea);
+                DisplayArea<? extends WindowContainer> imeContainer);
 
         /**
          * Instantiate the device-specific {@link Provider}.
diff --git a/services/core/java/com/android/server/wm/DisplayAreaPolicyBuilder.java b/services/core/java/com/android/server/wm/DisplayAreaPolicyBuilder.java
index e8becfa27facf..2c2f43392eca7 100644
--- a/services/core/java/com/android/server/wm/DisplayAreaPolicyBuilder.java
+++ b/services/core/java/com/android/server/wm/DisplayAreaPolicyBuilder.java
@@ -201,8 +201,8 @@ class DisplayAreaPolicyBuilder {
 
         Result(WindowManagerService wmService, DisplayContent content, DisplayArea.Root root,
                 DisplayArea<? extends WindowContainer> imeContainer,
-                DisplayArea<? extends ActivityStack> taskDisplayArea, ArrayList<Feature> features) {
-            super(wmService, content, root, imeContainer, taskDisplayArea);
+                List<TaskDisplayArea> taskDisplayAreas, ArrayList<Feature> features) {
+            super(wmService, content, root, imeContainer, taskDisplayAreas);
             mFeatures = features;
             mAreas = new HashMap<>(features.size());
             for (int i = 0; i < mFeatures.size(); i++) {
@@ -267,7 +267,7 @@ class DisplayAreaPolicyBuilder {
                     areaForLayer[layer].mChildren.add(leafArea);
                     leafType = type;
                     if (leafType == LEAF_TYPE_TASK_CONTAINERS) {
-                        leafArea.mExisting = mTaskContainers;
+                        addTaskDisplayAreasToLayer(areaForLayer[layer], layer);
                     } else if (leafType == LEAF_TYPE_IME_CONTAINERS) {
                         leafArea.mExisting = mImeContainer;
                     }
@@ -278,6 +278,17 @@ class DisplayAreaPolicyBuilder {
             root.instantiateChildren(mRoot, mAreaForLayer, 0, mAreas);
         }
 
+        /** Adds all task display areas to the specified layer */
+        private void addTaskDisplayAreasToLayer(PendingArea parentPendingArea, int layer) {
+            final int count = mTaskDisplayAreas.size();
+            for (int i = 0; i < count; i++) {
+                PendingArea leafArea = new PendingArea(null, layer, parentPendingArea);
+                leafArea.mExisting = mTaskDisplayAreas.get(i);
+                leafArea.mMaxLayer = layer;
+                parentPendingArea.mChildren.add(leafArea);
+            }
+        }
+
         @Override
         public void addWindow(WindowToken token) {
             DisplayArea.Tokens area = findAreaForToken(token);
@@ -317,12 +328,16 @@ class DisplayAreaPolicyBuilder {
         return this;
     }
 
+    protected List<Feature> getFeatures() {
+        return mFeatures;
+    }
+
     Result build(WindowManagerService wmService,
             DisplayContent content, DisplayArea.Root root,
             DisplayArea<? extends WindowContainer> imeContainer,
-            DisplayArea<? extends ActivityStack> taskDisplayArea) {
+            List<TaskDisplayArea> taskDisplayAreas) {
 
-        return new Result(wmService, content, root, imeContainer, taskDisplayArea, new ArrayList<>(
+        return new Result(wmService, content, root, imeContainer, taskDisplayAreas, new ArrayList<>(
                 mFeatures));
     }
 
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 2816633045b90..98d4b55d0c18b 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -72,6 +72,7 @@ import static android.view.WindowManager.LayoutParams.TYPE_WALLPAPER;
 import static android.view.WindowManager.TRANSIT_ACTIVITY_OPEN;
 import static android.view.WindowManager.TRANSIT_TASK_OPEN;
 import static android.view.WindowManager.TRANSIT_TASK_TO_FRONT;
+import static android.window.DisplayAreaOrganizer.FEATURE_DEFAULT_TASK_CONTAINER;
 
 import static com.android.server.policy.WindowManagerPolicy.FINISH_LAYOUT_REDO_ANIM;
 import static com.android.server.policy.WindowManagerPolicy.FINISH_LAYOUT_REDO_CONFIG;
@@ -268,8 +269,6 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
             new NonAppWindowContainers("mOverlayContainers", mWmService);
 
     /** The containers below are the only child containers {@link #mWindowContainers} can have. */
-    // Contains all window containers that are related to apps (Activities)
-    final TaskDisplayArea mTaskContainers = new TaskDisplayArea(this, mWmService);
 
     // Contains all IME window containers. Note that the z-ordering of the IME windows will depend
     // on the IME target. We mainly have this container grouping so we can keep track of all the IME
@@ -971,7 +970,7 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         super.addChild(mOverlayContainers, null);
 
         mDisplayAreaPolicy = mWmService.mDisplayAreaPolicyProvider.instantiate(
-                mWmService, this, mRootDisplayArea, mImeWindowsContainers, mTaskContainers);
+                mWmService, this, mRootDisplayArea, mImeWindowsContainers);
         mWindowContainers.addChildren();
 
         // Sets the display content for the children.
@@ -2069,13 +2068,11 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
     }
 
     protected int getTaskDisplayAreaCount() {
-        // TODO(multi-display-area): Report actual display area count
-        return 1;
+        return mDisplayAreaPolicy.getTaskDisplayAreaCount();
     }
 
     protected TaskDisplayArea getTaskDisplayAreaAt(int index) {
-        // TODO(multi-display-area): Report actual display area values
-        return mTaskContainers;
+        return mDisplayAreaPolicy.getTaskDisplayAreaAt(index);
     }
 
     ActivityStack getStack(int rootTaskId) {
@@ -2401,7 +2398,7 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
      * or for cases when multi-instance is not supported yet (like Split-screen, PiP or Recents).
      */
     TaskDisplayArea getDefaultTaskDisplayArea() {
-        return mTaskContainers;
+        return mDisplayAreaPolicy.getTaskDisplayAreaAt(0);
     }
 
     @Override
diff --git a/services/core/java/com/android/server/wm/TaskDisplayArea.java b/services/core/java/com/android/server/wm/TaskDisplayArea.java
index ec3c99bf08089..11cfad263fb21 100644
--- a/services/core/java/com/android/server/wm/TaskDisplayArea.java
+++ b/services/core/java/com/android/server/wm/TaskDisplayArea.java
@@ -31,7 +31,6 @@ import static android.app.WindowConfiguration.isSplitScreenWindowingMode;
 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_BEHIND;
 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSET;
 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
-import static android.window.DisplayAreaOrganizer.FEATURE_TASK_CONTAINER;
 
 import static com.android.server.wm.ActivityStack.ActivityState.RESUMED;
 import static com.android.server.wm.ActivityStack.STACK_VISIBILITY_VISIBLE;
@@ -141,8 +140,9 @@ final class TaskDisplayArea extends DisplayArea<ActivityStack> {
      */
     private boolean mRemoved;
 
-    TaskDisplayArea(DisplayContent displayContent, WindowManagerService service) {
-        super(service, Type.ANY, "TaskContainers", FEATURE_TASK_CONTAINER);
+    TaskDisplayArea(DisplayContent displayContent, WindowManagerService service, String name,
+            int displayAreaFeature) {
+        super(service, Type.ANY, name, displayAreaFeature);
         mDisplayContent = displayContent;
         mRootWindowContainer = service.mRoot;
         mAtmService = service.mAtmService;
diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaPolicyBuilderTest.java b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaPolicyBuilderTest.java
index 12bdec6ec1e1a..0568be8d7fa68 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaPolicyBuilderTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaPolicyBuilderTest.java
@@ -22,6 +22,7 @@ import static android.view.WindowManager.LayoutParams.TYPE_NAVIGATION_BAR;
 import static android.view.WindowManager.LayoutParams.TYPE_PRESENTATION;
 import static android.view.WindowManager.LayoutParams.TYPE_STATUS_BAR;
 import static android.view.WindowManagerPolicyConstants.APPLICATION_LAYER;
+import static android.window.DisplayAreaOrganizer.FEATURE_DEFAULT_TASK_CONTAINER;
 
 import static com.android.server.wm.DisplayArea.Type.ABOVE_TASKS;
 import static com.android.server.wm.DisplayArea.Type.ANY;
@@ -72,7 +73,11 @@ public class DisplayAreaPolicyBuilderTest {
         WindowManagerService wms = mSystemServices.getWindowManagerService();
         DisplayArea.Root root = new SurfacelessDisplayAreaRoot(wms);
         DisplayArea<WindowContainer> ime = new DisplayArea<>(wms, ABOVE_TASKS, "Ime");
-        DisplayArea<ActivityStack> tasks = new DisplayArea<>(wms, ANY, "Tasks");
+        DisplayContent displayContent = mock(DisplayContent.class);
+        TaskDisplayArea taskDisplayArea = new TaskDisplayArea(displayContent, wms, "Tasks",
+                FEATURE_DEFAULT_TASK_CONTAINER);
+        List<TaskDisplayArea> taskDisplayAreaList = new ArrayList<>();
+        taskDisplayAreaList.add(taskDisplayArea);
 
         final Feature foo;
         final Feature bar;
@@ -86,7 +91,7 @@ public class DisplayAreaPolicyBuilderTest {
                         .all()
                         .except(TYPE_STATUS_BAR)
                         .build())
-                .build(wms, mock(DisplayContent.class), root, ime, tasks);
+                .build(wms, displayContent, root, ime, taskDisplayAreaList);
 
         policy.attachDisplayAreas();
 
@@ -98,9 +103,9 @@ public class DisplayAreaPolicyBuilderTest {
         assertThat(policy.findAreaForToken(tokenOfType(TYPE_STATUS_BAR)),
                 is(not(decendantOfOneOf(policy.getDisplayAreas(bar)))));
 
-        assertThat(tasks,
+        assertThat(taskDisplayArea,
                 is(decendantOfOneOf(policy.getDisplayAreas(foo))));
-        assertThat(tasks,
+        assertThat(taskDisplayArea,
                 is(decendantOfOneOf(policy.getDisplayAreas(bar))));
 
         assertThat(ime,
@@ -109,7 +114,8 @@ public class DisplayAreaPolicyBuilderTest {
                 is(decendantOfOneOf(policy.getDisplayAreas(bar))));
 
         List<DisplayArea<?>> actualOrder = collectLeafAreas(root);
-        Map<DisplayArea<?>, Set<Integer>> zSets = calculateZSets(policy, root, ime, tasks);
+        Map<DisplayArea<?>, Set<Integer>> zSets = calculateZSets(policy, root, ime,
+                taskDisplayArea);
         actualOrder = actualOrder.stream().filter(zSets::containsKey).collect(toList());
 
         Map<DisplayArea<?>, Integer> expectedByMinLayer = mapValues(zSets,
diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaProviderTest.java b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaProviderTest.java
index 4e4627bf7e524..6834ee5f39507 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaProviderTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaProviderTest.java
@@ -77,8 +77,7 @@ public class DisplayAreaProviderTest {
 
         @Override
         public DisplayAreaPolicy instantiate(WindowManagerService wmService, DisplayContent content,
-                DisplayArea.Root root, DisplayArea<? extends WindowContainer> imeContainer,
-                TaskDisplayArea taskDisplayArea) {
+                DisplayArea.Root root, DisplayArea<? extends WindowContainer> imeContainer) {
             throw new RuntimeException("test stub");
         }
     }
diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaTest.java b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaTest.java
index 618e6086b582a..880c486c15af8 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayAreaTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayAreaTest.java
@@ -53,17 +53,6 @@ public class DisplayAreaTest {
         assertThrows(IllegalStateException.class, () -> parent.addChild(child, 0));
     }
 
-    @Test
-    public void testDisplayArea_positionChanged_throwsIfIncompatibleSibling() {
-        WindowManagerService wms = mWmsRule.getWindowManagerService();
-        DisplayArea<WindowContainer> parent = new SurfacelessDisplayArea<>(wms, ANY, "Parent");
-        DisplayArea<WindowContainer> child1 = new DisplayArea<>(wms, ANY, "Child1");
-        DisplayArea<WindowContainer> child2 = new DisplayArea<>(wms, ANY, "Child2");
-
-        parent.addChild(child1, 0);
-        assertThrows(IllegalStateException.class, () -> parent.addChild(child2, 0));
-    }
-
     @Test
     public void testType_typeOf() {
         WindowManagerService wms = mWmsRule.getWindowManagerService();
@@ -87,10 +76,10 @@ public class DisplayAreaTest {
         checkSiblings(BELOW_TASKS, ABOVE_TASKS);
         checkSiblings(ANY, ABOVE_TASKS);
         checkSiblings(ABOVE_TASKS, ABOVE_TASKS);
+        checkSiblings(ANY, ANY);
 
         assertThrows(IllegalStateException.class, () -> checkSiblings(ABOVE_TASKS, BELOW_TASKS));
         assertThrows(IllegalStateException.class, () -> checkSiblings(ABOVE_TASKS, ANY));
-        assertThrows(IllegalStateException.class, () -> checkSiblings(ANY, ANY));
         assertThrows(IllegalStateException.class, () -> checkSiblings(ANY, BELOW_TASKS));
     }
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/TaskDisplayAreaTests.java b/services/tests/wmtests/src/com/android/server/wm/TaskDisplayAreaTests.java
index 9625ffdac0525..a7085334bece1 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TaskDisplayAreaTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TaskDisplayAreaTests.java
@@ -51,10 +51,10 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 /**
- * Tests for the {@link DisplayContent.TaskStackContainers} container in {@link DisplayContent}.
+ * Tests for the {@link TaskDisplayArea} container.
  *
  * Build/Install/Run:
- *  atest WmTests:TaskStackContainersTests
+ *  atest WmTests:TaskDisplayAreaTests
  */
 @SmallTest
 @Presubmit
@@ -154,8 +154,9 @@ public class TaskDisplayAreaTests extends WindowTestsBase {
                 ACTIVITY_TYPE_STANDARD, mDisplayContent);
         final Task newStack = createTaskStackOnDisplay(WINDOWING_MODE_FULLSCREEN,
                 ACTIVITY_TYPE_STANDARD, mDisplayContent);
-        doReturn(newStack).when(mDisplayContent.mTaskContainers).createStack(anyInt(),
-                anyInt(), anyBoolean(), any(), any(), anyBoolean());
+        final TaskDisplayArea taskDisplayArea = candidateTask.getDisplayArea();
+        doReturn(newStack).when(taskDisplayArea).createStack(anyInt(), anyInt(), anyBoolean(),
+                any(), any(), anyBoolean());
 
         final int type = ACTIVITY_TYPE_STANDARD;
         assertGetOrCreateStack(WINDOWING_MODE_FULLSCREEN, type, candidateTask,
@@ -186,7 +187,7 @@ public class TaskDisplayAreaTests extends WindowTestsBase {
 
     private void assertGetOrCreateStack(int windowingMode, int activityType, Task candidateTask,
             boolean reuseCandidate) {
-        final TaskDisplayArea taskDisplayArea = (TaskDisplayArea) candidateTask.getParent();
+        final TaskDisplayArea taskDisplayArea = candidateTask.getDisplayArea();
         final ActivityStack stack = taskDisplayArea.getOrCreateStack(windowingMode, activityType,
                 false /* onTop */, null /* intent */, candidateTask /* candidateTask */);
         assertEquals(reuseCandidate, stack == candidateTask);
diff --git a/services/tests/wmtests/src/com/android/server/wm/TestDisplayContent.java b/services/tests/wmtests/src/com/android/server/wm/TestDisplayContent.java
index 18737c2b4bb74..57c750449d20c 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TestDisplayContent.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TestDisplayContent.java
@@ -43,7 +43,9 @@ class TestDisplayContent extends DisplayContent {
         // hard-code to FULLSCREEN for tests.
         setWindowingMode(WINDOWING_MODE_FULLSCREEN);
         spyOn(this);
-        spyOn(mTaskContainers);
+        for (int i = getTaskDisplayAreaCount() - 1; i >= 0; --i) {
+            spyOn(getTaskDisplayAreaAt(i));
+        }
 
         final DisplayRotation displayRotation = getDisplayRotation();
         spyOn(displayRotation);