Make channel preemption not require view contexts for hookup

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 
@@ skipping 1575 matching lines @@
   // the view hierarchy because the tab isn't main.  Could retrieve
   // the information from the main tab for our window.
   NSWindow* enclosing_window = ApparentWindowForView(cocoa_view_);
   if (!enclosing_window)
     return gfx::Rect();
 
   NSRect bounds = [enclosing_window frame];
   return FlipNSRectToRectScreen(bounds);
 }
 
-gfx::GLSurfaceHandle RenderWidgetHostViewMac::GetCompositingSurface() {
-  // TODO(kbr): may be able to eliminate PluginWindowHandle argument
-  // completely on Mac OS.
-  return gfx::GLSurfaceHandle(gfx::kNullPluginWindow, gfx::NULL_TRANSPORT);
-}
-
 bool RenderWidgetHostViewMac::LockMouse() {
   if (mouse_locked_)
     return true;
 
   mouse_locked_ = true;
 
   // Lock position of mouse cursor and hide it.
   CGAssociateMouseAndMouseCursorPosition(NO);
   [NSCursor hide];
 
@@ skipping 1858 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end