Send a message through the ozone channel to recreate buffers

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 b2152757bfc1979f357f4cd090da259e32336981..6bc43daa2345fa962f559ad06015cbdf3a2ef742 100644
--- a/ui/platform_window/platform_window_delegate.h
+++ b/ui/platform_window/platform_window_delegate.h
@@ -30,6 +30,8 @@ class PlatformWindowDelegate {
   // Note that |new_bounds| is in physical screen coordinates.
   virtual void OnBoundsChanged(const gfx::Rect& new_bounds) = 0;
 
+  virtual void OnChangedSurface() = 0;
+
   // Note that |damaged_region| is in the platform-window's coordinates, in
   // physical pixels.
   virtual void OnDamageRect(const gfx::Rect& damaged_region) = 0;