Merge "Ensure Surface is recreated if children are detached." into pi-dev

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

@@ -4297,6 +4297,15 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
         final boolean wasVisible = isVisibleLw();
 
         result |= (!wasVisible || !isDrawnLw()) ? RELAYOUT_RES_FIRST_TIME : 0;
+
+        if (mWinAnimator.mChildrenDetached) {
+            // If there are detached children hanging around we need to force
+            // the client receiving a new Surface.
+            mWinAnimator.preserveSurfaceLocked();
+            result |= RELAYOUT_RES_SURFACE_CHANGED
+                    | RELAYOUT_RES_FIRST_TIME;
+        }
+
         if (mAnimatingExit) {
             Slog.d(TAG, "relayoutVisibleWindow: " + this + " mAnimatingExit=true, mRemoveOnExit="
                     + mRemoveOnExit + ", mDestroying=" + mDestroying);

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

@@ -221,6 +221,10 @@ class WindowStateAnimator {
 
     private final SurfaceControl.Transaction mReparentTransaction = new SurfaceControl.Transaction();
 
+    // Used to track whether we have called detach children on the way to invisibility, in which
+    // case we need to give the client a new Surface if it lays back out to a visible state.
+    boolean mChildrenDetached = false;
+
     WindowStateAnimator(final WindowState win) {
         final WindowManagerService service = win.mService;
 
@@ -430,6 +434,7 @@ class WindowStateAnimator {
         if (mSurfaceController != null) {
             return mSurfaceController;
         }
+        mChildrenDetached = false;
 
         if ((mWin.mAttrs.privateFlags & PRIVATE_FLAG_IS_ROUNDED_CORNERS_OVERLAY) != 0) {
             windowType = SurfaceControl.WINDOW_TYPE_DONT_SCREENSHOT;
@@ -1478,6 +1483,7 @@ class WindowStateAnimator {
         if (mSurfaceController != null) {
             mSurfaceController.detachChildren();
         }
+        mChildrenDetached = true;
     }
 
     int getLayer() {