Revert of Flip flag to turn CrOS Browser Compositor Single Threaded

ui/compositor/test/in_process_context_factory.cc

Index: ui/compositor/test/in_process_context_factory.cc
diff --git a/ui/compositor/test/in_process_context_factory.cc b/ui/compositor/test/in_process_context_factory.cc
index d9e3dc4197de72d9f166b062399591292c8fdedf..d51120a07e32d7de587930a38d9c5e011efa9416 100644
--- a/ui/compositor/test/in_process_context_factory.cc
+++ b/ui/compositor/test/in_process_context_factory.cc
@@ -67,6 +67,17 @@
   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() {}