Delete mus surfaces hit testing

components/mus/ws/platform_display_delegate.h

Index: components/mus/ws/platform_display_delegate.h
diff --git a/components/mus/ws/platform_display_delegate.h b/components/mus/ws/platform_display_delegate.h
index a69857773b0e4f6f0b3cf46292c8ffb43e05f361..3ef3786f5df2218a12571790ab2304459c0d6b8e 100644
--- a/components/mus/ws/platform_display_delegate.h
+++ b/components/mus/ws/platform_display_delegate.h
@@ -8,10 +8,6 @@
 #include "components/mus/public/interfaces/window_tree.mojom.h"
 #include "components/mus/ws/ids.h"
 
-namespace cc {
-struct SurfaceId;
-}
-
 namespace ui {
 class Event;
 }
@@ -44,8 +40,6 @@ class PlatformDisplayDelegate {
       const mojom::ViewportMetrics& old_metrics,
       const mojom::ViewportMetrics& new_metrics) = 0;
 
-  virtual void OnTopLevelSurfaceChanged(cc::SurfaceId surface_id) = 0;
-
   // Called when a compositor frame is finished drawing.
   virtual void OnCompositorFrameDrawn() = 0;