Added a unique command buffer ID for command buffers.

ppapi/proxy/ppapi_command_buffer_proxy.h

Index: ppapi/proxy/ppapi_command_buffer_proxy.h
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.h b/ppapi/proxy/ppapi_command_buffer_proxy.h
index 3bf8eceed5e2abfa79c5e314aa7bdeb55fcbe8b9..d0c9c7e08de841bc0dc5a6c9504b0e82965fed3e 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.h
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.h
@@ -67,6 +67,8 @@ class PPAPI_PROXY_EXPORT PpapiCommandBufferProxy : public gpu::CommandBuffer,
   uint32 CreateStreamTexture(uint32 texture_id) override;
   void SetLock(base::Lock*) override;
   bool IsGpuChannelLost() override;
+  gpu::CommandBufferNamespace GetNamespaceID() const override;
+  uint64_t GetCommandBufferID() const override;
 
  private:
   bool Send(IPC::Message* msg);