Add GenericSharedMemoryId and use w/ GpuMemoryBuffer

content/browser/gpu/browser_gpu_memory_buffer_manager.h

Index: content/browser/gpu/browser_gpu_memory_buffer_manager.h
diff --git a/content/browser/gpu/browser_gpu_memory_buffer_manager.h b/content/browser/gpu/browser_gpu_memory_buffer_manager.h
index b11faf870219478a21913d2c5387edfbadb1c66b..dadff8621c97b1bcf7a9fba9303d959aa164dcb0 100644
--- a/content/browser/gpu/browser_gpu_memory_buffer_manager.h
+++ b/content/browser/gpu/browser_gpu_memory_buffer_manager.h
@@ -52,6 +52,7 @@ class CONTENT_EXPORT BrowserGpuMemoryBufferManager
       int32 surface_id);
 
   void AllocateGpuMemoryBufferForChildProcess(
+      gfx::GpuMemoryBufferId id,
       const gfx::Size& size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage,
@@ -90,6 +91,8 @@ class CONTENT_EXPORT BrowserGpuMemoryBufferManager
     int gpu_host_id;
   };
   struct AllocateGpuMemoryBufferRequest;
+  using BufferMap = base::hash_map<gfx::GpuMemoryBufferId, BufferInfo>;
+  using ClientMap = base::hash_map<int, BufferMap>;
 
   scoped_ptr<gfx::GpuMemoryBuffer> AllocateGpuMemoryBufferForSurface(
       const gfx::Size& size,
@@ -124,6 +127,12 @@ class CONTENT_EXPORT BrowserGpuMemoryBufferManager
 
   uint64_t ClientIdToTracingProcessId(int client_id) const;
 
+  // Helper that tries to add a new buffer to the map and returns false if not
+  // possible (because an element with the same id already existed).
+  bool TryAddNewBufferToMap(BufferMap& buffers,
+                            int id,
+                            const BufferInfo& buffer_info);
+
   const gfx::GpuMemoryBufferType factory_type_;
   const std::vector<GpuMemoryBufferFactory::Configuration>
       supported_configurations_;
@@ -135,8 +144,6 @@ class CONTENT_EXPORT BrowserGpuMemoryBufferManager
 
   // 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);