Workaround to ensure that PIP activities have a visible shadow.

- When the window for the activity enters PIP, update the outline provider
  to override the alpha of the shadow (to be opaque) to ensure that is is
  visible.  Only applies to the task root activity.

Bug: 36741700
Test: Launch YT, ensure that there is a shadow when after it enters PIP
Test: go/wm-smoke
Test: android.server.cts.ActivityManagerPinnedStackTests

Change-Id: If089dae84e4916d3d0e7bbeb316215b46e522e05
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarWindowView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarWindowView.java
index 236e008..f58a91b 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarWindowView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarWindowView.java
@@ -722,6 +722,10 @@
         }
 
         @Override
+        public void onPictureInPictureModeChanged(boolean isInPictureInPictureMode) {
+        }
+
+        @Override
         public void reportActivityRelaunched() {
         }
     };