WIP - compositor worker mega patch.

cc/test/fake_layer_tree_host_client.h

Index: cc/test/fake_layer_tree_host_client.h
diff --git a/cc/test/fake_layer_tree_host_client.h b/cc/test/fake_layer_tree_host_client.h
index 7e2ba030186275205c970a6e49bd8653ed6318c8..3e3c5a7d8f74d850277caa9a7f97d80bba327f1a 100644
--- a/cc/test/fake_layer_tree_host_client.h
+++ b/cc/test/fake_layer_tree_host_client.h
@@ -40,6 +40,8 @@ class FakeLayerTreeHostClient : public LayerTreeHostClient,
                            const gfx::Vector2dF& elastic_overscroll_delta,
                            float page_scale,
                            float top_controls_delta) override {}
+  void ApplyMutations(const LayerTreeMutationMap& mutations) override {}
+
   void RequestNewOutputSurface() override;
   void DidInitializeOutputSurface() override {}
   void DidFailToInitializeOutputSurface() override;