Merge "Set alpha to 0 on attach to avoid flicker at transition start." into udc-dev am: dc472531b8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23252176

Change-Id: Ic27840b48a7427818ae89b5fe733e5525763d6b0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipContentOverlay.java

@@ -206,6 +206,7 @@ public abstract class PipContentOverlay {
             tx.show(mLeash);
             tx.setLayer(mLeash, Integer.MAX_VALUE);
             tx.setBuffer(mLeash, mBitmap.getHardwareBuffer());
+            tx.setAlpha(mLeash, 0f);
             tx.reparent(mLeash, parentLeash);
             tx.apply();
         }