Introduce separate client and init path for single-threaded cc

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index ce5dfe1d921129bfca209d99a304cc05084923b6..d0874c4283f3f27423bd02adfe3c760269aecc82 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -1779,21 +1779,20 @@ class LayerTreeHostTestCannotCreateIfCannotCreateOutputSurface
   void RunTest(bool threaded,
                bool delegating_renderer,
                bool impl_side_painting) {
-    scoped_ptr<base::Thread> impl_thread;
+    LayerTreeSettings settings;
+    settings.impl_side_painting = impl_side_painting;
     if (threaded) {
-      impl_thread.reset(new base::Thread("LayerTreeTest"));
+      scoped_ptr<base::Thread> impl_thread(new base::Thread("LayerTreeTest"));
       ASSERT_TRUE(impl_thread->Start());
       ASSERT_TRUE(impl_thread->message_loop_proxy().get());
+      scoped_ptr<LayerTreeHost> layer_tree_host = LayerTreeHost::CreateThreaded(
+          this, NULL, settings, impl_thread->message_loop_proxy());
+      EXPECT_FALSE(layer_tree_host);
+    } else {
+      scoped_ptr<LayerTreeHost> layer_tree_host =
+          LayerTreeHost::CreateSingleThreaded(this, this, NULL, settings);
+      EXPECT_FALSE(layer_tree_host);
     }
-
-    LayerTreeSettings settings;
-    settings.impl_side_painting = impl_side_painting;
-    scoped_ptr<LayerTreeHost> layer_tree_host = LayerTreeHost::Create(
-        this,
-        NULL,
-        settings,
-        impl_thread ? impl_thread->message_loop_proxy() : NULL);
-    EXPECT_FALSE(layer_tree_host);
   }
 };