Add GPU memory usage contents browser test

content/public/common/gpu_memory_stats.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_PUBLIC_COMMON_GPU_MEMORY_STATS_H_
 #define CONTENT_PUBLIC_COMMON_GPU_MEMORY_STATS_H_
 
 // Provides access to the GPU information for the system
 // on which chrome is currently running.
 
@@ skipping 18 matching lines @@
 
     // Set to true if this process' GPU resource count is inflated because
     // it is counting other processes' resources (e.g, the GPU process has
     // duplicate set to true because it is the aggregate of all processes)
     bool has_duplicates;
   };
   typedef std::map<base::ProcessId, ProcessStats> ProcessMap;
 
   // A map of processes to their GPU resource consumption
   ProcessMap process_map;
+
+  // The total amount of GPU memory allocated at the time of the request.
+  size_t bytes_allocated;
+
+  // The maximum amount of GPU memory ever allocated at once.
+  size_t bytes_allocated_historical_max;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_GPU_MEMORY_STATS_H_