Show task background surface

It should be visible behind activity contents to draw stuff when task
resized while the activity is still resizing.

Bug: 241601214
Test: It shows behind activity contents.
Change-Id: I88af4d5b334223b6c4c4d4403d4a23e8fd56becf

2 files changed, 5 insertions, 1 deletions

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
index 087304b0d00b..506a4c0f90f3 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
@@ -233,7 +233,9 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
         mTmpColor[2] = (float) Color.blue(backgroundColorInt) / 255.f;
         startT.setWindowCrop(mTaskBackgroundSurface, taskBounds.width(), taskBounds.height())
                 .setShadowRadius(mTaskBackgroundSurface, shadowRadius)
-                .setColor(mTaskBackgroundSurface, mTmpColor);
+                .setColor(mTaskBackgroundSurface, mTmpColor)
+                .setLayer(mTaskBackgroundSurface, -1)
+                .show(mTaskBackgroundSurface);
 
         // Caption view
         mCaptionWindowManager.setConfiguration(taskConfig);
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/WindowDecorationTests.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/WindowDecorationTests.java
index 1e7d5fe95229..226843eca64e 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/WindowDecorationTests.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/WindowDecorationTests.java
@@ -204,6 +204,8 @@ public class WindowDecorationTests extends ShellTestCase {
         verify(mMockSurfaceControlStartT)
                 .setColor(taskBackgroundSurface, new float[] {1.f, 1.f, 0.f});
         verify(mMockSurfaceControlStartT).setShadowRadius(taskBackgroundSurface, 10);
+        verify(mMockSurfaceControlStartT).setLayer(taskBackgroundSurface, -1);
+        verify(mMockSurfaceControlStartT).show(taskBackgroundSurface);
 
         verify(mMockSurfaceControlViewHostFactory)
                 .create(any(), eq(defaultDisplay), any(), anyBoolean());