cc:: Change plumbing for external_begin_frame_source to the Scheduler.

cc/debug/micro_benchmark_controller_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 "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/debug/micro_benchmark.h"
 #include "cc/debug/micro_benchmark_controller.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_settings.h"
@@ skipping 17 matching lines @@
         make_scoped_ptr(new FakeImplTaskRunnerProvider);
     layer_tree_host_impl_ = make_scoped_ptr(new FakeLayerTreeHostImpl(
         impl_task_runner_provider_.get(), &shared_bitmap_manager_,
         &task_graph_runner_));
 
     layer_tree_host_ = FakeLayerTreeHost::Create(&layer_tree_host_client_,
                                                  &task_graph_runner_);
     layer_tree_host_->SetRootLayer(Layer::Create(LayerSettings()));
     layer_tree_host_->InitializeForTesting(
         TaskRunnerProvider::Create(nullptr, nullptr),
-        scoped_ptr<Proxy>(new FakeProxy));
+        scoped_ptr<Proxy>(new FakeProxy), nullptr);
   }
 
   void TearDown() override {
     layer_tree_host_impl_ = nullptr;
     layer_tree_host_ = nullptr;
     impl_task_runner_provider_ = nullptr;
   }
 
   FakeLayerTreeHostClient layer_tree_host_client_;
   TestTaskGraphRunner task_graph_runner_;
@@ skipping 124 matching lines @@
   // Send invalid message to valid benchmark
   message = make_scoped_ptr(new base::DictionaryValue);
   message->SetBoolean("can_handle", false);
   message_handled =
       layer_tree_host_->SendMessageToMicroBenchmark(id, std::move(message));
   EXPECT_FALSE(message_handled);
 }
 
 }  // namespace
 }  // namespace cc