Fix black screen on app transition.

The layer adjustment to an animating window upon completion was masking
the window behind the mWindowAnimationBackgroundSurface, a DimSurface.
The DimSurface was not being hidden because the step was happening too
late. Swapping the order of performAnimationsLocked and
updateWindowsAppsAndRotationAnimationsLocked fixes this ordering issue.

Fixes bug 6185920.

Change-Id: I0ff64c019e821fa3a92505ac6351f2648897e592

Author: Craig Mautner

services/java/com/android/server/wm/WindowManagerService.java

@@ -7688,9 +7688,9 @@ private void animateAndUpdateSurfaces(final long currentTime, final int dw, fina
         Surface.openTransaction();
 
         try {
+            updateWindowsAppsAndRotationAnimationsLocked(currentTime, innerDw, innerDh);
             mPendingLayoutChanges = performAnimationsLocked(currentTime, dw, dh,
                     innerDw, innerDh);
-            updateWindowsAppsAndRotationAnimationsLocked(currentTime, innerDw, innerDh);
 
             // THIRD LOOP: Update the surfaces of all windows.