Don't run DirectRenderer versions of LayerTreeTest unless explicit.

cc/output/delegating_renderer_unittest.cc

Index: cc/output/delegating_renderer_unittest.cc
diff --git a/cc/output/delegating_renderer_unittest.cc b/cc/output/delegating_renderer_unittest.cc
index a073033071c0a41470d54f77f7948fd8b16276a0..2af413d4a931a198187c086f75e3f5be62c16a7b 100644
--- a/cc/output/delegating_renderer_unittest.cc
+++ b/cc/output/delegating_renderer_unittest.cc
@@ -76,7 +76,7 @@ class DelegatingRendererTestDraw : public DelegatingRendererTest {
   gfx::Rect drawn_viewport_;
 };
 
-SINGLE_AND_MULTI_THREAD_DELEGATING_RENDERER_TEST_F(DelegatingRendererTestDraw);
+SINGLE_AND_MULTI_THREAD_TEST_F(DelegatingRendererTestDraw);
 
 class DelegatingRendererTestResources : public DelegatingRendererTest {
  public:
@@ -125,7 +125,6 @@ class DelegatingRendererTestResources : public DelegatingRendererTest {
   }
 };
 
-SINGLE_AND_MULTI_THREAD_DELEGATING_RENDERER_TEST_F(
-    DelegatingRendererTestResources);
+SINGLE_AND_MULTI_THREAD_TEST_F(DelegatingRendererTestResources);
 
 }  // namespace cc