command_buffer: Remove dead code for gl_begin_gl_end_on_fbo_change_to_backbuffer workaround

ui/gl/gl_surface.h

Index: ui/gl/gl_surface.h
diff --git a/ui/gl/gl_surface.h b/ui/gl/gl_surface.h
index 64906f663d21a41640f5f7c4f35f6a2487cdbc3b..e72ec1189077c2d59c5322ac2a7c8d03cf7632eb 100644
--- a/ui/gl/gl_surface.h
+++ b/ui/gl/gl_surface.h
@@ -135,10 +135,6 @@ class GL_EXPORT GLSurface : public base::RefCounted<GLSurface> {
   // on error.
   virtual bool OnMakeCurrent(GLContext* context);
 
-  // Called when the surface is bound as the current framebuffer for the
-  // current context.
-  virtual void NotifyWasBound();
-
   // Used for explicit buffer management.
   virtual bool SetBackbufferAllocation(bool allocated);
   virtual void SetFrontbufferAllocation(bool allocated);