Remove offscreen compositor contexts.

ui/compositor/compositor.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 "ui/compositor/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
@@ skipping 379 matching lines @@
 void Compositor::DidCompleteSwapBuffers() {
   if (g_compositor_thread) {
     NotifyEnd();
   } else {
     DCHECK_EQ(swap_state_, SWAP_POSTED);
     NotifyEnd();
     swap_state_ = SWAP_COMPLETED;
   }
 }
 
-scoped_refptr<cc::ContextProvider> Compositor::OffscreenContextProvider() {
-  return ContextFactory::GetInstance()->OffscreenCompositorContextProvider();
-}
-
 void Compositor::ScheduleComposite() {
   if (!disable_schedule_composite_)
     ScheduleDraw();
 }
 
 void Compositor::ScheduleAnimation() {
   ScheduleComposite();
 }
 
 void Compositor::DidPostSwapBuffers() {
@@ skipping 62 matching lines @@
     // CompositorObservers to be notified before starting another
     // draw cycle.
     ScheduleDraw();
   }
   FOR_EACH_OBSERVER(CompositorObserver,
                     observer_list_,
                     OnCompositingEnded(this));
 }
 
 }  // namespace ui