Add TransferBufferInterface::shared_memory_handle()

gpu/command_buffer/client/transfer_buffer.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 GPU_COMMAND_BUFFER_CLIENT_TRANSFER_BUFFER_H_
 #define GPU_COMMAND_BUFFER_CLIENT_TRANSFER_BUFFER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "gpu/command_buffer/client/ring_buffer.h"
 #include "gpu/command_buffer/common/buffer.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/gpu_export.h"
 
+namespace base {
+
+class SharedMemoryHandle;
+
+}  // namespace base
+
 namespace gpu {
 
 class CommandBufferHelper;
 
 // Interface for managing the transfer buffer.
 class GPU_EXPORT TransferBufferInterface {
  public:
   TransferBufferInterface() { }
   virtual ~TransferBufferInterface() { }
 
+  // Returns the shared memory's handle when the back end is base::SharedMemory.
+  // Otherwise, this returns an invalid handle.
+  virtual base::SharedMemoryHandle shared_memory_handle() const = 0;
+
   virtual bool Initialize(
       unsigned int buffer_size,
       unsigned int result_size,
       unsigned int min_buffer_size,
       unsigned int max_buffer_size,
       unsigned int alignment,
       unsigned int size_to_flush) = 0;
 
   virtual int GetShmId() = 0;
   virtual void* GetResultBuffer() = 0;
@@ skipping 21 matching lines @@
   virtual unsigned int GetFreeSize() const = 0;
 };
 
 // Class that manages the transfer buffer.
 class GPU_EXPORT TransferBuffer : public TransferBufferInterface {
  public:
   TransferBuffer(CommandBufferHelper* helper);
   ~TransferBuffer() override;
 
   // Overridden from TransferBufferInterface.
+  base::SharedMemoryHandle shared_memory_handle() const override;
   bool Initialize(unsigned int default_buffer_size,
                   unsigned int result_size,
                   unsigned int min_buffer_size,
                   unsigned int max_buffer_size,
                   unsigned int alignment,
                   unsigned int size_to_flush) override;
   int GetShmId() override;
   void* GetResultBuffer() override;
   int GetResultOffset() override;
   void Free() override;
@@ skipping 131 matching lines @@
   }
 
   unsigned int num_elements() const {
     return size() / sizeof(T);
   }
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_TRANSFER_BUFFER_H_