Add a new ozone switch to enable surfaceless output mode.

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index 17b05485e2100548e11665e3def068bad5f42db1..6ed6f65ed4cfa53b062bc8d9dcd0d6d6197f4d11 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -225,13 +225,21 @@ scoped_ptr<cc::OutputSurface> GpuProcessTransportFactory::CreateOutputSurface(
     return surface.PassAs<cc::OutputSurface>();
   }
 
-  scoped_ptr<BrowserCompositorOutputSurface> surface(
-      new GpuBrowserCompositorOutputSurface(
-          context_provider,
-          per_compositor_data_[compositor]->surface_id,
-          &output_surface_map_,
-          compositor->vsync_manager(),
-          CreateOverlayCandidateValidator(compositor->widget())));
+  scoped_ptr<BrowserCompositorOutputSurface> surface;
+#if defined(USE_OZONE)
+  if (ui::SurfaceFactoryOzone::GetInstance()->CanShowPrimaryPlaneAsOverlay()) {
+    NOTIMPLEMENTED();
+    return scoped_ptr<cc::OutputSurface>();  // TODO(achaulk) implementation.
+  }
+#endif
+  if (!surface)
+    surface.reset(new GpuBrowserCompositorOutputSurface(
+        context_provider,
+        per_compositor_data_[compositor]->surface_id,
+        &output_surface_map_,
+        compositor->vsync_manager(),
+        CreateOverlayCandidateValidator(compositor->widget())));
+
   if (data->reflector.get())
     data->reflector->ReattachToOutputSurfaceFromMainThread(surface.get());