Remove external begin frame source parameter and settings

cc/trees/channel_main.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_TREES_CHANNEL_MAIN_H_
 #define CC_TREES_CHANNEL_MAIN_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/base/completion_event.h"
 #include "cc/input/top_controls_state.h"
@@ skipping 44 matching lines @@
       base::TimeTicks main_thread_start_time,
       std::vector<std::unique_ptr<SwapPromise>> swap_promises) = 0;
   virtual void NotifyReadyToCommitOnImpl(
       CompletionEvent* completion,
       LayerTreeHostInProcess* layer_tree_host,
       base::TimeTicks main_thread_start_time,
       bool hold_commit_for_activation) = 0;
 
   // Must be called before using the channel.
   virtual void SynchronouslyInitializeImpl(
-      LayerTreeHostInProcess* layer_tree_host,
-      std::unique_ptr<BeginFrameSource> external_begin_frame_source) = 0;
+      LayerTreeHostInProcess* layer_tree_host) = 0;
 
   // Must be called before deleting the channel.
   virtual void SynchronouslyCloseImpl() = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_CHANNEL_MAIN_H_