cc: Make LayerTreeTests use a DelegatingRenderer and Display.

cc/test/layer_tree_pixel_test.h

Index: cc/test/layer_tree_pixel_test.h
diff --git a/cc/test/layer_tree_pixel_test.h b/cc/test/layer_tree_pixel_test.h
index 3ab75b4824c8ce64b1cd6ac50941b34e2e77a31a..3e266cb2b9f590a10005c03bbc50b45db4650509 100644
--- a/cc/test/layer_tree_pixel_test.h
+++ b/cc/test/layer_tree_pixel_test.h
@@ -41,8 +41,11 @@ class LayerTreePixelTest : public LayerTreeTest {
   ~LayerTreePixelTest() override;
 
   // LayerTreeTest overrides.
-  void InitializeSettings(LayerTreeSettings* settings) override;
-  std::unique_ptr<OutputSurface> CreateOutputSurface() override;
+  std::unique_ptr<TestDelegatingOutputSurface> CreateDelegatingOutputSurface(
+      scoped_refptr<ContextProvider> compositor_context_provider,
+      scoped_refptr<ContextProvider> worker_context_provider) override;
+  std::unique_ptr<OutputSurface> CreateDisplayOutputSurface(
+      scoped_refptr<ContextProvider> compositor_context_provider) override;
 
   virtual std::unique_ptr<CopyOutputRequest> CreateCopyOutputRequest();