Revert of Flip flag to turn CrOS Browser Compositor Single Threaded

content/browser/compositor/gpu_process_transport_factory.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_process_transport_factory.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 56 matching lines @@
   int surface_id;
   scoped_refptr<ReflectorImpl> reflector;
   scoped_ptr<OnscreenDisplayClient> display_client;
 };
 
 GpuProcessTransportFactory::GpuProcessTransportFactory()
     : next_surface_id_namespace_(1u),
       callback_factory_(this) {
   output_surface_proxy_ = new BrowserCompositorOutputSurfaceProxy(
       &output_surface_map_);
-
+#if defined(OS_CHROMEOS)
+  bool use_thread = !base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUIDisableThreadedCompositing);
+#else
+  bool use_thread = false;
+#endif
+  if (use_thread) {
+    compositor_thread_.reset(new base::Thread("Browser Compositor"));
+    compositor_thread_->Start();
+  }
   if (UseSurfacesEnabled())
     surface_manager_ = make_scoped_ptr(new cc::SurfaceManager);
 }
 
 GpuProcessTransportFactory::~GpuProcessTransportFactory() {
   DCHECK(per_compositor_data_.empty());
 
   // Make sure the lost context callback doesn't try to run during destruction.
   callback_factory_.InvalidateWeakPtrs();
 }
@@ skipping 143 matching lines @@
     output_surface->set_display_client(display_client.get());
     display_client->display()->Resize(compositor->size());
     data->display_client = display_client.Pass();
     compositor->SetOutputSurface(output_surface.Pass());
     return;
   }
 
   if (!context_provider.get()) {
     if (compositor_thread_.get()) {
       LOG(FATAL) << "Failed to create UI context, but can't use software"
-                    " compositing with browser threaded compositing. Aborting.";
+                 " compositing with browser threaded compositing. Aborting.";
     }
 
     scoped_ptr<SoftwareBrowserCompositorOutputSurface> surface(
         new SoftwareBrowserCompositorOutputSurface(
             output_surface_proxy_,
             CreateSoftwareOutputDevice(compositor.get()),
             data->surface_id,
             &output_surface_map_,
             compositor->vsync_manager()));
     compositor->SetOutputSurface(surface.Pass());
@@ skipping 276 matching lines @@
   FOR_EACH_OBSERVER(ImageTransportFactoryObserver,
                     observer_list_,
                     OnLostResources());
 
   // Kill things that use the shared context before killing the shared context.
   lost_gl_helper.reset();
   lost_shared_main_thread_contexts  = NULL;
 }
 
 }  // namespace content