aura: Support SurfaceDestroyed() on Android

ui/platform_window/platform_window_delegate.h

Index: ui/platform_window/platform_window_delegate.h
diff --git a/ui/platform_window/platform_window_delegate.h b/ui/platform_window/platform_window_delegate.h
index 67c63a7e5e41f94f9c69ddbe32ff7bd415e7755a..f7cdb1abf3ddbc992fff7255ab2ea33f851cb3be 100644
--- a/ui/platform_window/platform_window_delegate.h
+++ b/ui/platform_window/platform_window_delegate.h
@@ -46,6 +46,10 @@ class PlatformWindowDelegate {
   virtual void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget,
                                             float device_pixel_ratio) = 0;
 
+  // Notifies the delegate that the widget cannot be used anymore until
+  // a new widget is made available through OnAcceleratedWidgetAvailable().
+  virtual void OnAcceleratedWidgetDestroyed() = 0;
+
   virtual void OnActivationChanged(bool active) = 0;
 };