Provide shared context to Platform API in renderer.

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 62 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(PendingSwap);
 };
 
 class NullContextProvider : public cc::ContextProvider {
  public:
   virtual bool InitializeOnMainThread() OVERRIDE { return false; }
   virtual bool BindToCurrentThread() OVERRIDE { return false; }
   virtual WebKit::WebGraphicsContext3D* Context3d() OVERRIDE { return NULL; }
   virtual class GrContext* GrContext() OVERRIDE { return NULL; }
   virtual void VerifyContexts() OVERRIDE {}
+  virtual bool DestroyedOnMainThread() OVERRIDE { return false; }
 
  protected:
   virtual ~NullContextProvider() {}
 };
 
 struct MainThreadNullContextProvider {
   scoped_refptr<NullContextProvider> provider;
 
   static MainThreadNullContextProvider* GetInstance() {
     return Singleton<MainThreadNullContextProvider>::get();
@@ skipping 597 matching lines @@
 
 COMPOSITOR_EXPORT void DisableTestCompositor() {
   g_test_compositor_enabled = false;
 }
 
 COMPOSITOR_EXPORT bool IsTestCompositorEnabled() {
   return g_test_compositor_enabled;
 }
 
 }  // namespace ui