GLContextNSView should not assume concrete type GLSurface is GLSurfaceNSView

ui/gfx/gl/gl_context_nsview.mm

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/gl/gl_context_nsview.h"
 
 #include <vector>
 
 #import <AppKit/NSOpenGL.h>
 #import <AppKit/NSView.h>
@@ skipping 28 matching lines @@
     return false;
   }
 
   context_.reset([[NSOpenGLContext alloc] initWithFormat:pixel_format
                                             shareContext:nil]);
   if (!context_) {
     LOG(ERROR) << "NSOpenGLContext initWithFormat failed";
     return false;
   }
 
-  // Allow the surface to call back when in need of |FlushBuffer|.
-  static_cast<GLSurfaceNSView*>(surface)->SetGLContext(this);
-
   return true;
 }
 
 void GLContextNSView::Destroy() {
   context_.reset(nil);
 }
 
 bool GLContextNSView::MakeCurrent(GLSurface* surface) {
   PluginWindowHandle view =
       static_cast<PluginWindowHandle>(surface->GetHandle());
   // Only set the context's view if the view is parented.
   // I.e. it is a valid drawable.
   if ([view window])
     [context_ setView:view];
   [context_ makeCurrentContext];
+
+  if (!surface->OnMakeCurrent(this)) {
+    LOG(ERROR) << "Unable to make gl context current.";
+    return false;
+  }
+
   return true;
 }
 
 void GLContextNSView::ReleaseCurrent(GLSurface* surface) {
   [NSOpenGLContext clearCurrentContext];
 }
 
 bool GLContextNSView::IsCurrent(GLSurface* surface) {
   return context_ == [NSOpenGLContext currentContext];
 }
 
 void* GLContextNSView::GetHandle() {
   return context_;
 }
 
 void GLContextNSView::SetSwapInterval(int interval) {
   DCHECK(interval == 0 || interval == 1);
   GLint swap = interval;
   [context_ setValues:&swap forParameter:NSOpenGLCPSwapInterval];
 }
 
 void GLContextNSView::FlushBuffer() {
   [context_ flushBuffer];
 }
 
 }  // namespace gfx