Remove external begin frame source parameter and settings

cc/layers/layer_unittest.cc

 // Copyright 2011 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/layer.h"
 
 #include <stddef.h>
 
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/animation/animation_host.h"
@@ skipping 889 matching lines @@
 
 class MockLayerTreeHost : public LayerTreeHostInProcess {
  public:
   MockLayerTreeHost(LayerTreeHostSingleThreadClient* single_thread_client,
                     LayerTreeHostInProcess::InitParams* params)
       : LayerTreeHostInProcess(
             params,
             CompositorMode::SINGLE_THREADED,
             base::MakeUnique<StrictMock<MockLayerTree>>(params, this)) {
     InitializeSingleThreaded(single_thread_client,
-                             base::ThreadTaskRunnerHandle::Get(), nullptr);
+                             base::ThreadTaskRunnerHandle::Get());
   }
 
   MOCK_METHOD0(SetNeedsCommit, void());
   MOCK_METHOD0(SetNeedsUpdateLayers, void());
 };
 
 class LayerTest : public testing::Test {
  public:
   LayerTest()
       : host_impl_(LayerTreeSettings(),
@@ skipping 1633 matching lines @@
   EXPECT_EQ(MutableProperty::kNone, impl_layer->mutable_properties());
 
   test_layer->PushPropertiesTo(impl_layer.get());
 
   EXPECT_EQ(ElementId(2, 0), impl_layer->element_id());
   EXPECT_EQ(MutableProperty::kTransform, impl_layer->mutable_properties());
 }
 
 }  // namespace
 }  // namespace cc