Revert of Flip flag to turn CrOS Browser Compositor Single Threaded

ui/compositor/test/in_process_context_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 "ui/compositor/test/in_process_context_factory.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/threading/thread.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 49 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(DirectOutputSurface);
 };
 
 }  // namespace
 
 InProcessContextFactory::InProcessContextFactory()
     : next_surface_id_namespace_(1u), use_test_surface_(true) {
   DCHECK_NE(gfx::GetGLImplementation(), gfx::kGLImplementationNone)
       << "If running tests, ensure that main() is calling "
       << "gfx::GLSurface::InitializeOneOffForTests()";
+
+#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();
+  }
 }
 
 InProcessContextFactory::~InProcessContextFactory() {}
 
 void InProcessContextFactory::CreateOutputSurface(
     base::WeakPtr<Compositor> compositor,
     bool software_fallback) {
   DCHECK(!software_fallback);
   gpu::gles2::ContextCreationAttribHelper attribs;
   attribs.alpha_size = 8;
@@ skipping 70 matching lines @@
 InProcessContextFactory::CreateSurfaceIdAllocator() {
   return make_scoped_ptr(
       new cc::SurfaceIdAllocator(next_surface_id_namespace_++));
 }
 
 void InProcessContextFactory::ResizeDisplay(ui::Compositor* compositor,
                                             const gfx::Size& size) {
 }
 
 }  // namespace ui