Remove offscreen compositor contexts.

cc/test/fake_output_surface_client.cc

 // Copyright 2013 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 "cc/test/fake_output_surface_client.h"
 
 namespace cc {
 
-bool FakeOutputSurfaceClient::DeferredInitialize(
-    scoped_refptr<ContextProvider> offscreen_context_provider) {
+void FakeOutputSurfaceClient::DeferredInitialize() {
   deferred_initialize_called_ = true;
-  return deferred_initialize_result_;
 }
 
 void FakeOutputSurfaceClient::BeginFrame(const BeginFrameArgs& args) {
   begin_frame_count_++;
 }
 
 void FakeOutputSurfaceClient::DidLoseOutputSurface() {
   did_lose_output_surface_called_ = true;
 }
 
 void FakeOutputSurfaceClient::SetMemoryPolicy(
     const ManagedMemoryPolicy& policy) {
   memory_policy_ = policy;
 }
 
 }  // namespace cc