Fix window shadows.

ui/base/cocoa/underlay_opengl_hosting_window.h

Index: ui/base/cocoa/underlay_opengl_hosting_window.h
diff --git a/ui/base/cocoa/underlay_opengl_hosting_window.h b/ui/base/cocoa/underlay_opengl_hosting_window.h
index caa3cf0ae2e6ad6bd5fbaa64853c823b8805a41f..d3123622750121c3fc2ccb9b453d7592fca8db68 100644
--- a/ui/base/cocoa/underlay_opengl_hosting_window.h
+++ b/ui/base/cocoa/underlay_opengl_hosting_window.h
@@ -8,26 +8,10 @@
 
 #import <Cocoa/Cocoa.h>
 
-// Protocol implemented by windows that need to be informed explicitly about
-// underlay surfaces.
-@protocol UnderlayableSurface
-- (void)underlaySurfaceAdded;
-- (void)underlaySurfaceRemoved;
-@end
-
 // Common base class for windows that host a OpenGL surface that renders under
 // the window. Contains methods relating to hole punching so that the OpenGL
 // surface is visible through the window.
-@interface UnderlayOpenGLHostingWindow : NSWindow<UnderlayableSurface> {
- @private
-  int underlaySurfaceCount_;
-}
-
-// Informs the window that an underlay surface has been added/removed. The
-// window is non-opaque while underlay surfaces are present.
-- (void)underlaySurfaceAdded;
-- (void)underlaySurfaceRemoved;
-
+@interface UnderlayOpenGLHostingWindow : NSWindow
 @end
 
 #endif  // UI_BASE_COCOA_UNDERLAY_OPENGL_HOSTING_WINDOW_H_