Remove external begin frame source parameter and settings

cc/layers/ui_resource_layer_unittest.cc

 // Copyright 2013 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/layers/ui_resource_layer.h"
 
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/scoped_ui_resource.h"
 #include "cc/test/fake_layer_tree_host.h"
@@ skipping 33 matching lines @@
   TestUIResourceLayer() : UIResourceLayer() { SetIsDrawable(true); }
   ~TestUIResourceLayer() override {}
 };
 
 class UIResourceLayerTest : public testing::Test {
  protected:
   void SetUp() override {
     layer_tree_host_ =
         FakeLayerTreeHost::Create(&fake_client_, &task_graph_runner_);
     layer_tree_host_->InitializeSingleThreaded(
-        &single_thread_client_, base::ThreadTaskRunnerHandle::Get(), nullptr);
+        &single_thread_client_, base::ThreadTaskRunnerHandle::Get());
   }
 
   void TearDown() override {
     Mock::VerifyAndClearExpectations(layer_tree_host_.get());
   }
 
   FakeLayerTreeHostClient fake_client_;
   StubLayerTreeHostSingleThreadClient single_thread_client_;
   TestTaskGraphRunner task_graph_runner_;
   std::unique_ptr<FakeLayerTreeHost> layer_tree_host_;
@@ skipping 70 matching lines @@
 
   test_layer->SetBitmap(bitmap);
   ASSERT_FALSE(bitmap.pixelRef()->unique());
 
   test_layer->SetUIResourceId(0);
   EXPECT_TRUE(bitmap.pixelRef()->unique());
 }
 
 }  // namespace
 }  // namespace cc