[Pepper GL] Use shared state to fix a memory leak in MapSub GL extension.

ppapi/proxy/ppapi_command_buffer_proxy.h

 // 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.
 
 #ifndef PPAPI_PROXY_COMMAND_BUFFER_PROXY_H_
 #define PPAPI_PROXY_COMMAND_BUFFER_PROXY_H_
 
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
+#include "base/memory/scoped_ptr.h"
 #include "gpu/command_buffer/client/gpu_control.h"
 #include "gpu/command_buffer/common/command_buffer.h"
+#include "gpu/command_buffer/common/command_buffer_shared.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 #include "ppapi/shared_impl/host_resource.h"
 
 namespace IPC {
 class Message;
 }
 
 namespace ppapi {
 namespace proxy {
 
 class ProxyChannel;
+class SerializedHandle;
 
 class PPAPI_PROXY_EXPORT PpapiCommandBufferProxy : public gpu::CommandBuffer,
                                                    public gpu::GpuControl {
  public:
   PpapiCommandBufferProxy(const HostResource& resource,
-                          ProxyChannel* channel);
+                          ProxyChannel* channel,
+                          const SerializedHandle& shared_state);
   virtual ~PpapiCommandBufferProxy();
 
   // gpu::CommandBuffer implementation:
   virtual bool Initialize() OVERRIDE;
   virtual State GetLastState() OVERRIDE;
   virtual int32 GetLastToken() OVERRIDE;
   virtual void Flush(int32 put_offset) OVERRIDE;
   virtual void WaitForTokenInRange(int32 start, int32 end) OVERRIDE;
   virtual void WaitForGetOffsetInRange(int32 start, int32 end) OVERRIDE;
   virtual void SetGetBuffer(int32 transfer_buffer_id) OVERRIDE;
@@ skipping 17 matching lines @@
   virtual void SignalQuery(uint32 query,
                            const base::Closure& callback) OVERRIDE;
   virtual void SetSurfaceVisible(bool visible) OVERRIDE;
   virtual void Echo(const base::Closure& callback) OVERRIDE;
   virtual uint32 CreateStreamTexture(uint32 texture_id) OVERRIDE;
 
  private:
   bool Send(IPC::Message* msg);
   void UpdateState(const gpu::CommandBuffer::State& state, bool success);
 
+  // Try to read an updated copy of the state from shared memory.
+  void TryUpdateState();
+
+  // The shared memory area used to update state.
+  gpu::CommandBufferSharedState* shared_state() const;
+
   State last_state_;
+  scoped_ptr<base::SharedMemory> shared_state_shm_;
 
   HostResource resource_;
   ProxyChannel* channel_;
 
   base::Closure channel_error_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(PpapiCommandBufferProxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif // PPAPI_PROXY_COMMAND_BUFFER_PROXY_H_