Refactor gpu::Buffer to allow different types of backing

gpu/command_buffer/service/common_decoder_unittest.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/common_decoder.h"
 #include "gpu/command_buffer/service/cmd_buffer_engine.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace gpu {
 
@@ skipping 65 matching lines @@
   static const size_t kBufferSize = 1024;
   static const int32 kValidOffset = kBufferSize / 2;
   static const int32 kInvalidOffset = kBufferSize;
 
   MockCommandBufferEngine()
       : CommandBufferEngine(),
         token_(),
         get_offset_(0) {
     scoped_ptr<base::SharedMemory> shared_memory(new base::SharedMemory());
     shared_memory->CreateAndMapAnonymous(kBufferSize);
-    buffer_ = new gpu::Buffer(shared_memory.Pass(), kBufferSize);
+    buffer_ = MakeBufferFromSharedMemory(shared_memory.Pass(), kBufferSize);
   }
 
   // Overridden from CommandBufferEngine.
   virtual scoped_refptr<gpu::Buffer> GetSharedMemoryBuffer(int32 shm_id)
       OVERRIDE {
     if (IsValidSharedMemoryId(shm_id))
       return buffer_;
     return NULL;
   }
 
@@ skipping 409 matching lines @@
            MockCommandBufferEngine::kValidShmId, kSomeOffsetInSharedMemory);
   EXPECT_NE(error::kNoError, ExecuteCmd(cmd));
 
   // Check that it fails if the size is invalid
   cmd.Init(kBucketId, 0, sizeof(kData) + 1,
            MockCommandBufferEngine::kValidShmId, kSomeOffsetInSharedMemory);
   EXPECT_NE(error::kNoError, ExecuteCmd(cmd));
 }
 
 }  // namespace gpu