Expose GpuMemoryBufferId through glGetImageivCHROMIUM.

gpu/command_buffer/client/gpu_control.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 GPU_COMMAND_BUFFER_CLIENT_GPU_CONTROL_H_
 #define GPU_COMMAND_BUFFER_CLIENT_GPU_CONTROL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 41 matching lines @@
   // Destroy an image. The ID must be positive.
   virtual void DestroyImage(int32_t id) = 0;
 
   // Create a gpu memory buffer backed image with the given dimensions and
   // format for |usage|. Returns its ID or -1 on error.
   virtual int32_t CreateGpuMemoryBufferImage(size_t width,
                                              size_t height,
                                              unsigned internalformat,
                                              unsigned usage) = 0;
 
+  // Returns the id of the GpuMemoryBuffer associated with the given image. If
+  // the image doesn't exist, or isn't associated with a GpuMemoryBuffer,
+  // returns -1.
+  virtual int32_t GetImageGpuMemoryBufferId(unsigned image_id) = 0;
+
   // Runs |callback| when a query created via glCreateQueryEXT() has cleared
   // passed the glEndQueryEXT() point.
   virtual void SignalQuery(uint32_t query, const base::Closure& callback) = 0;
 
   // Sets a lock this will be held on every callback from the GPU
   // implementation. This lock must be set and must be held on every call into
   // the GPU implementation if it is to be used from multiple threads. This
   // may not be supported with all implementations.
   virtual void SetLock(base::Lock*) = 0;
 
@@ skipping 36 matching lines @@
   // be enqueued first so does not need to be flushed.
   virtual bool CanWaitUnverifiedSyncToken(const SyncToken* sync_token) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GpuControl);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GPU_CONTROL_H_