Merge "Set alpha to 0 on attach to avoid flicker at transition start." into udc-dev am: dc472531b8 am: bdb153f5ad am: 2900187577

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

Change-Id: I488e27d6b91e97430013116f1bbbcde63b5519a4
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();
         }