Request a traversal when a saved surface gets redrawn

When a saved surface gets redrawn, we need to return true in
finishDrawingLocked, so that a traversal is requested. This is
needed to update allDrawn/allDrawnExcludingSaved. Some delayed
window removal may be waiting for these flags.

bug: 28797800
Change-Id: I0b58b356e9c580422eb3ff81e8afb2a164cf6e43

services/core/java/com/android/server/wm/WindowState.java

@@ -2115,14 +2115,16 @@ final class WindowState implements WindowManagerPolicy.WindowState {
         mWasVisibleBeforeClientHidden = false;
     }
 
-    void clearAnimatingWithSavedSurface() {
+    boolean clearAnimatingWithSavedSurface() {
         if (mAnimatingWithSavedSurface) {
             // App has drawn something to its windows, we're no longer animating with
             // the saved surfaces.
             if (DEBUG_ANIM) Slog.d(TAG,
                     "clearAnimatingWithSavedSurface(): win=" + this);
             mAnimatingWithSavedSurface = false;
+            return true;
         }
+        return false;
     }
 
     @Override

services/core/java/com/android/server/wm/WindowStateAnimator.java

@@ -585,7 +585,7 @@ class WindowStateAnimator {
                     + drawStateToString());
         }
 
-        mWin.clearAnimatingWithSavedSurface();
+        boolean layoutNeeded = mWin.clearAnimatingWithSavedSurface();
 
         if (mDrawState == DRAW_PENDING) {
             if (DEBUG_SURFACE_TRACE || DEBUG_ANIM || SHOW_TRANSACTIONS || DEBUG_ORIENTATION)
@@ -595,10 +595,10 @@ class WindowStateAnimator {
                 Slog.v(TAG, "Draw state now committed in " + mWin);
             }
             mDrawState = COMMIT_DRAW_PENDING;
-            return true;
+            layoutNeeded = true;
         }
 
-        return false;
+        return layoutNeeded;
     }
 
     // This must be called while inside a transaction.