gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/gles2_implementation.h

Index: gpu/command_buffer/client/gles2_implementation.h
diff --git a/gpu/command_buffer/client/gles2_implementation.h b/gpu/command_buffer/client/gles2_implementation.h
index 6b6877f18b3bc74b7f92b7d08a469f42a53668d1..b496a88c7c8a7feba3cdaacb370b2a47ffceb746 100644
--- a/gpu/command_buffer/client/gles2_implementation.h
+++ b/gpu/command_buffer/client/gles2_implementation.h
@@ -591,6 +591,21 @@ class GLES2_IMPL_EXPORT GLES2Implementation
 
   void OnSwapBuffersComplete();
 
+  // Free transfer buffer if unused token already passed, or free pending
+  // the unused token if not.
+  void FreeTransferBuffer(BufferTracker::Buffer* buffer);
+
+  // Free and remove buffer if no async upload in progress. If in progress,
+  // unmanage the buffer and free and destroy when upload completed.
+  void DisposeTransferBuffer(BufferTracker::Buffer* buffer);
+
+  // Used for keeping track of async upload buffers.
+  void CheckBuffersPendingAsyncComplete();
+
+  // Internal async upload query.
+  void BeginQueryAsyncPixelUnpackCompleted(BufferTracker::Buffer *buffer);
+  void EndQueryAsyncPixelUnpackCompleted();
+
   bool GetBoundPixelTransferBuffer(
       GLenum target, const char* function_name, GLuint* buffer_id);
   BufferTracker::Buffer* GetBoundPixelUnpackTransferBufferIfValid(
@@ -699,8 +714,11 @@ class GLES2_IMPL_EXPORT GLES2Implementation
 
   scoped_ptr<QueryTracker> query_tracker_;
   QueryTracker::Query* current_query_;
+  QueryTracker::Query* current_private_unpack_query_;
 
   scoped_ptr<BufferTracker> buffer_tracker_;
+  typedef std::list<BufferTracker::Buffer*> BufferList;
+  BufferList released_buffers_pending_async_complete_;
 
   scoped_ptr<GpuMemoryBufferTracker> gpu_memory_buffer_tracker_;