cc: Make LayerTreeTests use a DelegatingRenderer and Display.

cc/surfaces/display_unittest.cc

Index: cc/surfaces/display_unittest.cc
diff --git a/cc/surfaces/display_unittest.cc b/cc/surfaces/display_unittest.cc
index 74c650802d2111bf5455bbefa9bff3b5f2c95cbc..51e7fd6fca7cb1611714d6fc3e80074c1274f5ea 100644
--- a/cc/surfaces/display_unittest.cc
+++ b/cc/surfaces/display_unittest.cc
@@ -164,6 +164,9 @@ class StubDisplayClient : public DisplayClient {
  public:
   void DisplayOutputSurfaceLost() override {}
   void DisplaySetMemoryPolicy(const ManagedMemoryPolicy& policy) override {}
+  void DisplayWillDrawAndSwap(bool will_draw_and_swap,
+                              const RenderPassList& render_passes) override {}
+  void DisplayDidDrawAndSwap() override {}
 };
 
 void CopyCallback(bool* called, std::unique_ptr<CopyOutputResult> result) {