Remove external begin frame source parameter and settings

cc/animation/animation_host_perftest.cc

Index: cc/animation/animation_host_perftest.cc
diff --git a/cc/animation/animation_host_perftest.cc b/cc/animation/animation_host_perftest.cc
index ca20b3ed23454ebeea3b5df7d5e3748ab1b967f0..c20fcd97f9b2d7c8aa072c4f6939ba0bc378aa5e 100644
--- a/cc/animation/animation_host_perftest.cc
+++ b/cc/animation/animation_host_perftest.cc
@@ -35,7 +35,7 @@ class AnimationHostPerfTest : public testing::Test {
     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_);