Make GPU back-pressure work with remote CALayers

content/common/gpu/image_transport_surface_fbo_mac.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_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_FBO_MAC_H_
 #define CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_FBO_MAC_H_
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/gpu/gpu_command_buffer_stub.h"
@@ skipping 27 matching lines @@
         gfx::Size size, float scale_factor) = 0;
 
     // Free the storage allocated in the AllocateColorBufferStorage call. The
     // GL texture that was bound has already been deleted by the caller.
     virtual void FreeColorBufferStorage() = 0;
 
     // Retrieve the handle for the surface to send to the browser process to
     // display.
     virtual uint64 GetSurfaceHandle() const = 0;
 
-    // Called when a frame is about to be sent to the browser process.
+    // Called when a new frame has been rendered into the texture, and the
+    // browser is about to be sent the surface to display.
     virtual void WillSwapBuffers() = 0;
+
+    // Called once for every WillSwapBuffers call when the buffer that was sent
+    // to the browser may be released by the GPU process (this may be because
+    // the browser is holding a reference, in which case this will come
+    // quickly, or it may be because the browser is done with the surface, in
+    // which case it will come much later).
+    virtual void CanFreeSwappedBuffer() = 0;
   };
 
-  ImageTransportSurfaceFBO(StorageProvider* storage_provider,
-                           GpuChannelManager* manager,
+  ImageTransportSurfaceFBO(GpuChannelManager* manager,
                            GpuCommandBufferStub* stub,
                            gfx::PluginWindowHandle handle);
 
   // GLSurface implementation
   virtual bool Initialize() OVERRIDE;
   virtual void Destroy() OVERRIDE;
   virtual bool DeferDraws() OVERRIDE;
   virtual bool IsOffscreen() OVERRIDE;
   virtual bool SwapBuffers() OVERRIDE;
   virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE;
   virtual bool SupportsPostSubBuffer() OVERRIDE;
   virtual gfx::Size GetSize() OVERRIDE;
   virtual void* GetHandle() OVERRIDE;
   virtual void* GetDisplay() OVERRIDE;
   virtual bool OnMakeCurrent(gfx::GLContext* context) OVERRIDE;
   virtual unsigned int GetBackingFrameBufferObject() OVERRIDE;
   virtual bool SetBackbufferAllocation(bool allocated) OVERRIDE;
   virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
 
+  // Called when the context may continue to make forward progress after a swap.
+  void UnblockContextAfterPendingSwap();
+
  protected:
   // ImageTransportSurface implementation
   virtual void OnBufferPresented(
       const AcceleratedSurfaceMsg_BufferPresented_Params& params) OVERRIDE;
   virtual void OnResize(gfx::Size size, float scale_factor) OVERRIDE;
   virtual void SetLatencyInfo(
       const std::vector<ui::LatencyInfo>&) OVERRIDE;
   virtual void WakeUpGpu() OVERRIDE;
 
   // GpuCommandBufferStub::DestructionObserver implementation.
@@ skipping 36 matching lines @@
   std::vector<ui::LatencyInfo> latency_info_;
 
   scoped_ptr<ImageTransportHelper> helper_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageTransportSurfaceFBO);
 };
 
 }  // namespace content
 
 #endif  //  CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_MAC_H_