Refactor gpu::Buffer to allow different types of backing

content/common/gpu/client/command_buffer_proxy_impl.cc

Index: content/common/gpu/client/command_buffer_proxy_impl.cc
diff --git a/content/common/gpu/client/command_buffer_proxy_impl.cc b/content/common/gpu/client/command_buffer_proxy_impl.cc
index 3cf28b67e1360904a2972329036cd2eef94f8326..f6d0feaabd515f01f2710b9569edb4b1371c67c9 100644
--- a/content/common/gpu/client/command_buffer_proxy_impl.cc
+++ b/content/common/gpu/client/command_buffer_proxy_impl.cc
@@ -286,8 +286,8 @@ scoped_refptr<gpu::Buffer> CommandBufferProxyImpl::CreateTransferBuffer(
   }
 
   *id = new_id;
-  scoped_refptr<gpu::Buffer> buffer =
-      new gpu::Buffer(shared_memory.Pass(), size);
+  scoped_refptr<gpu::Buffer> buffer(
+      gpu::MakeBufferFromSharedMemory(shared_memory.Pass(), size));
   return buffer;
 }