GPU Channel's now maintain a global order number for each processed IPC.

content/common/gpu/gpu_command_buffer_stub.h

 // 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.
 
 #ifndef CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_
 #define CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_
 
 #include <deque>
 #include <string>
 #include <vector>
@@ skipping 267 matching lines @@
 
   GpuWatchdog* watchdog_;
 
   base::ObserverList<DestructionObserver> destruction_observers_;
 
   // A queue of sync points associated with this stub.
   std::deque<uint32> sync_points_;
   int sync_point_wait_count_;
 
   bool delayed_work_scheduled_;
-  uint64 previous_messages_processed_;
+  uint32_t previous_processed_num_;
   base::TimeTicks last_idle_time_;
 
   scoped_refptr<gpu::PreemptionFlag> preemption_flag_;
 
   LatencyInfoCallback latency_info_callback_;
 
   GURL active_url_;
   size_t active_url_hash_;
 
   size_t total_gpu_memory_;
   scoped_ptr<WaitForCommandState> wait_for_token_;
   scoped_ptr<WaitForCommandState> wait_for_get_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuCommandBufferStub);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_