Mac Overlays: Add GPU back-pressure

content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc

 // 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.
 
 #include "content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.h"
 
 #include "cc/output/compositor_frame.h"
 #include "content/browser/compositor/browser_compositor_overlay_candidate_validator.h"
 #include "content/browser/compositor/buffer_queue.h"
 #include "content/browser/compositor/reflector_impl.h"
@@ skipping 80 matching lines @@
     const gfx::Size& size,
     float scale_factor) {
   GpuBrowserCompositorOutputSurface::Reshape(size, scale_factor);
   DCHECK(output_surface_);
   output_surface_->Reshape(SurfaceSize(), scale_factor);
 }
 
 void GpuSurfacelessBrowserCompositorOutputSurface::OnSwapBuffersCompleted(
     const std::vector<ui::LatencyInfo>& latency_info,
     gfx::SwapResult result) {
+#if defined(OS_MACOSX)
+  NOTREACHED();
+#else
   if (result == gfx::SwapResult::SWAP_NAK_RECREATE_BUFFERS) {
     // Even through the swap failed, this is a fixable error so we can pretend
     // it succeeded to the rest of the system.
     result = gfx::SwapResult::SWAP_ACK;
     output_surface_->RecreateBuffers();
   }
   GpuBrowserCompositorOutputSurface::OnSwapBuffersCompleted(latency_info,
                                                             result);
+#endif
 }
 
 #if defined(OS_MACOSX)
 void GpuSurfacelessBrowserCompositorOutputSurface::OnSurfaceDisplayed() {
   OnSwapBuffersComplete();
 }
 #endif
 
 }  // namespace content