cc: Split Proxy and TaskRunnerProvider for the LayerTreeHost

cc/test/fake_proxy.h

Index: cc/test/fake_proxy.h
diff --git a/cc/test/fake_proxy.h b/cc/test/fake_proxy.h
index d2b9b384fa70bbc4a762e49653a210013a37efcc..7998625ef77082a26b5345c409947d46d5bbbec0 100644
--- a/cc/test/fake_proxy.h
+++ b/cc/test/fake_proxy.h
@@ -13,11 +13,7 @@ namespace cc {
 
 class FakeProxy : public Proxy {
  public:
-  FakeProxy() : Proxy(NULL, NULL), layer_tree_host_(NULL) {}
-  explicit FakeProxy(
-      scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
-      : Proxy(main_task_runner, impl_task_runner), layer_tree_host_(NULL) {}
+  FakeProxy() : layer_tree_host_(nullptr) {}
 
   void SetLayerTreeHost(LayerTreeHost* host);