Clean up GPU back-pressure with remote CALayers

content/common/gpu/image_transport_surface.h

Index: content/common/gpu/image_transport_surface.h
diff --git a/content/common/gpu/image_transport_surface.h b/content/common/gpu/image_transport_surface.h
index 19f6881b05fd0aa41b033f84a60da0f0fe97cbde..525e20f9d36986a46c838ca61501720b4cc116de 100644
--- a/content/common/gpu/image_transport_surface.h
+++ b/content/common/gpu/image_transport_surface.h
@@ -142,8 +142,10 @@ class ImageTransportHelper
   gpu::gles2::GLES2Decoder* Decoder();
 
   // IPC::Message handlers.
+#if defined(OS_MACOSX)
   void OnBufferPresented(
       const AcceleratedSurfaceMsg_BufferPresented_Params& params);
+#endif
   void OnWakeUpGpu();
 
   // Backbuffer resize callback.
@@ -180,8 +182,10 @@ class PassThroughImageTransportSurface
   virtual bool OnMakeCurrent(gfx::GLContext* context) override;
 
   // ImageTransportSurface implementation.
+#if defined(OS_MACOSX)
   virtual void OnBufferPresented(
       const AcceleratedSurfaceMsg_BufferPresented_Params& params) override;
+#endif
   virtual void OnResize(gfx::Size size, float scale_factor) override;
   virtual gfx::Size GetSize() override;
   virtual void SetLatencyInfo(