Remove code only used by Mac single threaded compositing.

content/browser/renderer_host/render_widget_host_impl.cc

 // 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_impl.h"
 
 #include <math.h>
 #include <set>
 #include <utility>
 
@@ skipping 819 matching lines @@
     TRACE_EVENT_ASYNC_BEGIN0(
         "renderer_host", "RenderWidgetHostImpl::repaint_ack_pending_", this);
     Send(new ViewMsg_Repaint(routing_id_, view_size));
   }
 
   TimeDelta max_delay = TimeDelta::FromMilliseconds(kPaintMsgTimeoutMS);
   TimeTicks end_time = TimeTicks::Now() + max_delay;
   do {
     TRACE_EVENT0("renderer_host", "GetBackingStore::WaitForUpdate");
 
-#if defined(OS_MACOSX)
-    view_->AboutToWaitForBackingStoreMsg();
-#endif
-
     // When we have asked the RenderWidget to resize, and we are still waiting
     // on a response, block for a little while to see if we can't get a response
     // before returning the old (incorrectly sized) backing store.
     IPC::Message msg;
     if (process_->WaitForBackingStoreMsg(routing_id_, max_delay, &msg)) {
       OnMessageReceived(msg);
 
       // For auto-resized views, current_size_ determines the view_size and it
       // may have changed during the handling of an UpdateRect message.
       if (should_auto_resize_)
@@ skipping 1614 matching lines @@
         continue;
       }
       RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(rwh);
       if (rwhi_set.insert(rwhi).second)
         rwhi->FrameSwapped(latency_info);
     }
   }
 }
 
 }  // namespace content