Refactor gpu::Buffer to allow different types of backing

gpu/command_buffer/service/command_buffer_service.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/command_buffer_service.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/debug/trace_event.h"
@@ skipping 85 matching lines @@
   num_entries_ = size / sizeof(CommandBufferEntry);
   put_offset_ = 0;
   SetGetOffset(0);
   if (!get_buffer_change_callback_.is_null()) {
     get_buffer_change_callback_.Run(ring_buffer_id_);
   }
 
   UpdateState();
 }
 
-bool CommandBufferService::SetSharedStateBuffer(
-    scoped_ptr<base::SharedMemory> shared_state_shm) {
-  shared_state_shm_.reset(shared_state_shm.release());
-  if (!shared_state_shm_->Map(sizeof(*shared_state_)))
-    return false;
+void CommandBufferService::SetSharedStateBuffer(
+    scoped_ptr<BufferBacking> shared_state_buffer) {
+  shared_state_buffer_ = shared_state_buffer.Pass();
+  DCHECK(shared_state_buffer_->GetSize() >= sizeof(*shared_state_));
 
   shared_state_ =
-      static_cast<CommandBufferSharedState*>(shared_state_shm_->memory());
+      static_cast<CommandBufferSharedState*>(shared_state_buffer_->GetMemory());
 
   UpdateState();
-  return true;
 }
 
 void CommandBufferService::SetGetOffset(int32 get_offset) {
   DCHECK(get_offset >= 0 && get_offset < num_entries_);
   get_offset_ = get_offset;
 }
 
 scoped_refptr<Buffer> CommandBufferService::CreateTransferBuffer(size_t size,
                                                                  int32* id) {
   *id = -1;
 
   scoped_ptr<SharedMemory> shared_memory(new SharedMemory());
   if (!shared_memory->CreateAndMapAnonymous(size))
     return NULL;
 
   static int32 next_id = 1;
   *id = next_id++;
 
-  if (!RegisterTransferBuffer(*id, shared_memory.Pass(), size)) {
+  if (!RegisterTransferBuffer(
+          *id, MakeBackingFromSharedMemory(shared_memory.Pass(), size))) {
     *id = -1;
     return NULL;
   }
 
   return GetTransferBuffer(*id);
 }
 
 void CommandBufferService::DestroyTransferBuffer(int32 id) {
   transfer_buffer_manager_->DestroyTransferBuffer(id);
   if (id == ring_buffer_id_) {
     ring_buffer_id_ = -1;
     ring_buffer_ = NULL;
     num_entries_ = 0;
     get_offset_ = 0;
     put_offset_ = 0;
   }
 }
 
 scoped_refptr<Buffer> CommandBufferService::GetTransferBuffer(int32 id) {
   return transfer_buffer_manager_->GetTransferBuffer(id);
 }
 
 bool CommandBufferService::RegisterTransferBuffer(
     int32 id,
-    scoped_ptr<base::SharedMemory> shared_memory,
-    size_t size) {
-  return transfer_buffer_manager_->RegisterTransferBuffer(
-      id, shared_memory.Pass(), size);
+    scoped_ptr<BufferBacking> buffer) {
+  return transfer_buffer_manager_->RegisterTransferBuffer(id, buffer.Pass());
 }
 
 void CommandBufferService::SetToken(int32 token) {
   token_ = token;
   UpdateState();
 }
 
 void CommandBufferService::SetParseError(error::Error error) {
   if (error_ == error::kNoError) {
     error_ = error;
@@ skipping 16 matching lines @@
     const GetBufferChangedCallback& callback) {
   get_buffer_change_callback_ = callback;
 }
 
 void CommandBufferService::SetParseErrorCallback(
     const base::Closure& callback) {
   parse_error_callback_ = callback;
 }
 
 }  // namespace gpu