Refactor gpu::Buffer to allow different types of backing

gpu/command_buffer/service/transfer_buffer_manager.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 "gpu/command_buffer/service/transfer_buffer_manager.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 22 matching lines @@
   }
   DCHECK(!shared_memory_bytes_allocated_);
 }
 
 bool TransferBufferManager::Initialize() {
   return true;
 }
 
 bool TransferBufferManager::RegisterTransferBuffer(
     int32 id,
-    scoped_ptr<base::SharedMemory> shared_memory,
-    size_t size) {
+    scoped_ptr<BufferBacking> buffer_backing) {
   if (id <= 0) {
     DVLOG(0) << "Cannot register transfer buffer with non-positive ID.";
     return false;
   }
 
   // Fail if the ID is in use.
   if (registered_buffers_.find(id) != registered_buffers_.end()) {
     DVLOG(0) << "Buffer ID already in use.";
     return false;
   }
 
   // Register the shared memory with the ID.
-  scoped_refptr<Buffer> buffer = new gpu::Buffer(shared_memory.Pass(), size);
+  scoped_refptr<Buffer> buffer(new gpu::Buffer(buffer_backing.Pass()));
 
   // Check buffer alignment is sane.
   DCHECK(!(reinterpret_cast<uintptr_t>(buffer->memory()) &
            (kCommandBufferEntrySize - 1)));
 
-  shared_memory_bytes_allocated_ += size;
+  shared_memory_bytes_allocated_ += buffer->size();
   TRACE_COUNTER_ID1(
       "gpu", "GpuTransferBufferMemory", this, shared_memory_bytes_allocated_);
 
   registered_buffers_[id] = buffer;
 
   return true;
 }
 
 void TransferBufferManager::DestroyTransferBuffer(int32 id) {
   BufferMap::iterator it = registered_buffers_.find(id);
@@ skipping 16 matching lines @@
 
   BufferMap::iterator it = registered_buffers_.find(id);
   if (it == registered_buffers_.end())
     return NULL;
 
   return it->second;
 }
 
 }  // namespace gpu