Clean up Mac swap acknowledgement code

content/browser/compositor/offscreen_browser_compositor_output_surface.h

 // Copyright 2015 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_BROWSER_COMPOSITOR_OFFSCREEN_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 #define CONTENT_BROWSER_COMPOSITOR_OFFSCREEN_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 
 #include "base/cancelable_callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 23 matching lines @@
   // cc::OutputSurface:
   void EnsureBackbuffer() override;
   void DiscardBackbuffer() override;
   void Reshape(const gfx::Size& size, float scale_factor) override;
   void BindFramebuffer() override;
   void SwapBuffers(cc::CompositorFrame* frame) override;
 
   // BrowserCompositorOutputSurface
   void OnReflectorChanged() override;
   base::Closure CreateCompositionStartedCallback() override;
+  void OnGpuSwapBuffersCompleted(
+      const std::vector<ui::LatencyInfo>& latency_info,
+      gfx::SwapResult result) override{};
 #if defined(OS_MACOSX)
-  void OnSurfaceDisplayed() override {};
   void SetSurfaceSuspendedForRecycle(bool suspended) override {};
   bool SurfaceShouldNotShowFramesAfterSuspendForRecycle() const override;
 #endif
 
   uint32 fbo_;
   bool is_backbuffer_discarded_;
   scoped_ptr<ReflectorTexture> reflector_texture_;
 
   base::WeakPtrFactory<OffscreenBrowserCompositorOutputSurface>
       weak_ptr_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(OffscreenBrowserCompositorOutputSurface);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_OFFSCREEN_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_