Remove external begin frame source parameter and settings

cc/animation/animation_host_perftest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/animation/animation_host.h"
 
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/animation/animation_id_provider.h"
 #include "cc/animation/animation_player.h"
 #include "cc/animation/animation_timeline.h"
@@ skipping 17 matching lines @@
         first_timeline_id_(),
         last_timeline_id_(),
         first_player_id_(),
         last_player_id_() {}
 
   void SetUp() override {
     LayerTreeSettings settings;
     layer_tree_host_ =
         FakeLayerTreeHost::Create(&fake_client_, &task_graph_runner_, settings);
     layer_tree_host_->InitializeSingleThreaded(
-        &single_thread_client_, base::ThreadTaskRunnerHandle::Get(), nullptr);
+        &single_thread_client_, base::ThreadTaskRunnerHandle::Get());
 
     root_layer_ = Layer::Create();
     layer_tree_host_->SetRootLayer(root_layer_);
 
     root_layer_impl_ = layer_tree_host_->CommitAndCreateLayerImplTree();
   }
 
   void TearDown() override {
     root_layer_ = nullptr;
     root_layer_impl_ = nullptr;
@@ skipping 112 matching lines @@
   CreateTimelines(10);
   DoTest();
 }
 
 TEST_F(AnimationHostPerfTest, Push1000TimelinesPropertiesTo) {
   CreateTimelines(1000);
   DoTest();
 }
 
 }  // namespace cc