gpu: Use a local int to generate the gmb id.

content/browser/gpu/browser_gpu_memory_buffer_manager.h

 // Copyright 2014 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_BROWSER_GPU_BROWSER_GPU_MEMORY_BUFFER_MANAGER_H_
 #define CONTENT_BROWSER_GPU_BROWSER_GPU_MEMORY_BUFFER_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 105 matching lines @@
                                   GpuProcessHost::BufferCreationStatus status);
   void DestroyGpuMemoryBufferOnIO(gfx::GpuMemoryBufferId id,
                                   int client_id,
                                   const gpu::SyncToken& sync_token);
 
   uint64_t ClientIdToTracingProcessId(int client_id) const;
 
   const gpu::GpuMemoryBufferConfigurationSet native_configurations_;
   const int gpu_client_id_;
   const uint64_t gpu_client_tracing_id_;
+  int next_gpu_memory_id_ = 1;
 
   // Stores info about buffers for all clients. This should only be accessed
   // on the IO thread.
   using BufferMap = base::hash_map<gfx::GpuMemoryBufferId, BufferInfo>;
   using ClientMap = base::hash_map<int, BufferMap>;
   ClientMap clients_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserGpuMemoryBufferManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_BROWSER_GPU_MEMORY_BUFFER_MANAGER_H_