Adds BeginFrameControl via DevTools.

content/browser/web_contents/web_contents_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.
 
 #import <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 388 matching lines @@
   // when the "zoom" button in the browser window is clicked.
   host->EnablePreferredSizeMode();
 }
 
 void WebContentsViewMac::RenderViewSwappedIn(RenderViewHost* host) {
 }
 
 void WebContentsViewMac::SetOverscrollControllerEnabled(bool enabled) {
 }
 
+ui::Compositor* WebContentsViewMac::GetCompositor() const {
+  return nullptr;
+}
+
 bool WebContentsViewMac::IsEventTracking() const {
   return base::MessagePumpMac::IsHandlingSendEvent();
 }
 
 // Arrange to call CloseTab() after we're back to the main event loop.
 // The obvious way to do this would be PostNonNestableTask(), but that
 // will fire when the event-tracking loop polls for events.  So we
 // need to bounce the message via Cocoa, instead.
 void WebContentsViewMac::CloseTabAfterEventTracking() {
   [cocoa_view_ cancelDeferredClose];
@@ skipping 299 matching lines @@
 
 - (void)viewDidHide {
   [self updateWebContentsVisibility];
 }
 
 - (void)viewDidUnhide {
   [self updateWebContentsVisibility];
 }
 
 @end