Add flow control between renderer and GPU processes, and, on Mac OS X,...

gpu/command_buffer/service/gpu_processor.h

 // Copyright (c) 2009 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_SERVICE_GPU_PROCESSOR_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GPU_PROCESSOR_H_
 
 #include <vector>
 
 #include "app/surface/transport_dib.h"
@@ skipping 67 matching lines @@
   // available in Mac OS X 10.6; and, one for use with the
   // TransportDIB-based version used on Mac OS X 10.5.
   virtual uint64 SetWindowSizeForIOSurface(const gfx::Size& size);
   virtual TransportDIB::Handle SetWindowSizeForTransportDIB(
       const gfx::Size& size);
   virtual void SetTransportDIBAllocAndFree(
       Callback2<size_t, TransportDIB::Handle*>::Type* allocator,
       Callback1<TransportDIB::Id>::Type* deallocator);
   // Returns the id of the current IOSurface, or 0.
   virtual uint64 GetSurfaceId();
+  // To prevent the GPU process from overloading the browser process,
+  // we need to track the number of swap buffers calls issued and
+  // acknowledged per on-screen (IOSurface-backed) context, and keep
+  // the GPU from getting too far ahead of the browser. Note that this
+  // is also predicated on a flow control mechanism between the
+  // renderer and GPU processes.
+  uint64 swap_buffers_count() const;
+  void set_acknowledged_swap_buffers_count(
+      uint64 acknowledged_swap_buffers_count);
 #endif
 
   // Sets a callback which is called when a SwapBuffers command is processed.
   // Must be called after Initialize().
   // It is not defined on which thread this callback is called.
   virtual void SetSwapBuffersCallback(Callback0::Type* callback);
 
   // Get the GLES2Decoder associated with this processor.
   gles2::GLES2Decoder* decoder() const { return decoder_.get(); }
 
@@ skipping 17 matching lines @@
   // through the ProcessCommands callback.
   CommandBuffer* command_buffer_;
 
   int commands_per_update_;
 
   scoped_ptr<gles2::GLES2Decoder> decoder_;
   scoped_ptr<CommandParser> parser_;
 
 #if defined(OS_MACOSX)
   scoped_ptr<AcceleratedSurface> surface_;
+  uint64 swap_buffers_count_;
+  uint64 acknowledged_swap_buffers_count_;
 #endif
 
   ScopedRunnableMethodFactory<GPUProcessor> method_factory_;
   scoped_ptr<Callback0::Type> wrapped_swap_buffers_callback_;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_PROCESSOR_H_