cc:: Change plumbing for external_begin_frame_source to the Scheduler.

cc/test/proxy_main_for_test.h

 // Copyright 2015 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.
 
 #ifndef CC_TEST_PROXY_MAIN_FOR_TEST_H_
 #define CC_TEST_PROXY_MAIN_FOR_TEST_H_
 
 #include "base/macros.h"
 #include "cc/test/test_hooks.h"
 #include "cc/trees/proxy_main.h"
 
 namespace cc {
 
 // Creates a ProxyMain that notifies the supplied |test_hooks| of various
 // actions.
 class ProxyMainForTest : public ProxyMain {
  public:
   static scoped_ptr<ProxyMain> CreateThreaded(
       TestHooks* test_hooks,
       LayerTreeHost* host,
-      TaskRunnerProvider* task_runner_provider,
-      scoped_ptr<BeginFrameSource> external_begin_frame_source);
+      TaskRunnerProvider* task_runner_provider);
 
   ~ProxyMainForTest() override;
 
   ProxyMainForTest(TestHooks* test_hooks,
                    LayerTreeHost* host,
-                   TaskRunnerProvider* task_runner_provider,
-                   scoped_ptr<BeginFrameSource> external_begin_frame_source);
+                   TaskRunnerProvider* task_runner_provider);
 
   void SetNeedsUpdateLayers() override;
   void DidCompleteSwapBuffers() override;
   void SetRendererCapabilities(
       const RendererCapabilities& capabilities) override;
   void BeginMainFrameNotExpectedSoon() override;
   void DidCommitAndDrawFrame() override;
   void SetAnimationEvents(scoped_ptr<AnimationEventsVector> events) override;
   void DidLoseOutputSurface() override;
   void RequestNewOutputSurface() override;
   void DidInitializeOutputSurface(
       bool success,
       const RendererCapabilities& capabilities) override;
   void DidCompletePageScaleAnimation() override;
   void PostFrameTimingEventsOnMain(
       scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
       scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events)
       override;
   void BeginMainFrame(
       scoped_ptr<BeginMainFrameAndCommitState> begin_main_frame_state) override;
 
   TestHooks* test_hooks_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_PROXY_MAIN_FOR_TEST_H_