Fix crash with pepper 3D on multiple windows in same renderer

chrome/renderer/pepper_platform_context_3d_impl.h

 // Copyright (c) 2010 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.
 #ifndef CHROME_RENDERER_PEPPER_PLATFORM_CONTEXT_3D_IMPL_H_
 #define CHROME_RENDERER_PEPPER_PLATFORM_CONTEXT_3D_IMPL_H_
 
 #include "base/callback.h"
 #include "base/scoped_callback_factory.h"
 #include "base/scoped_ptr.h"
+#include "base/weak_ptr.h"
 #include "webkit/plugins/ppapi/plugin_delegate.h"
 
 #ifdef ENABLE_GPU
 
 namespace gpu {
 
 class CommandBuffer;
 
 }  // namespace gpu
 
@@ skipping 15 matching lines @@
   virtual bool Init();
   virtual void SetSwapBuffersCallback(Callback0::Type* callback);
   virtual unsigned GetBackingTextureId();
   virtual gpu::CommandBuffer* GetCommandBuffer();
   virtual void SetContextLostCallback(Callback0::Type* callback);
 
  private:
   bool InitRaw();
   void OnContextLost();
 
-  ggl::Context* parent_context_;
+  base::WeakPtr<ggl::Context> parent_context_;
   scoped_refptr<GpuChannelHost> channel_;
   unsigned int parent_texture_id_;
   CommandBufferProxy* command_buffer_;
   scoped_ptr<Callback0::Type> context_lost_callback_;
   base::ScopedCallbackFactory<PlatformContext3DImpl> callback_factory_;
 };
 
 #endif  // ENABLE_GPU
 
 #endif  // CHROME_RENDERER_PEPPER_PLATFORM_CONTEXT_3D_IMPL_H_