gpu: Reuse transfer buffers more aggresively

ppapi/proxy/ppapi_command_buffer_proxy.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 "ppapi/proxy/ppapi_command_buffer_proxy.h"
 
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/proxy_channel.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/host_resource.h"
@@ skipping 171 matching lines @@
   buffer.shared_memory = shared_memory.release();
   transfer_buffers_[id] = buffer;
 
   return buffer;
 }
 
 void PpapiCommandBufferProxy::SetToken(int32 token) {
   NOTREACHED();
 }
 
+void PpapiCommandBufferProxy::SetSerial(uint32 serial) {
+  NOTREACHED();
+}
+
 void PpapiCommandBufferProxy::SetParseError(gpu::error::Error error) {
   NOTREACHED();
 }
 
 void PpapiCommandBufferProxy::SetContextLostReason(
     gpu::error::ContextLostReason reason) {
   NOTREACHED();
 }
 
 uint32 PpapiCommandBufferProxy::InsertSyncPoint() {
@@ skipping 72 matching lines @@
       last_state_ = state;
     }
   } else {
     last_state_.error = gpu::error::kLostContext;
     ++last_state_.generation;
   }
 }
 
 }  // namespace proxy
 }  // namespace ppapi