Remove external begin frame source parameter and settings

cc/trees/proxy.h

 // 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.
 
 #ifndef CC_TREES_PROXY_H_
 #define CC_TREES_PROXY_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 47 matching lines @@
   // Defers commits until it is reset. It is only supported when using a
   // scheduler.
   virtual void SetDeferCommits(bool defer_commits) = 0;
 
   virtual void MainThreadHasStoppedFlinging() = 0;
 
   virtual bool CommitRequested() const = 0;
   virtual bool BeginMainFrameRequested() const = 0;
 
   // Must be called before using the proxy.
-  virtual void Start(
-      std::unique_ptr<BeginFrameSource> external_begin_frame_source) = 0;
-  virtual void Stop() = 0;   // Must be called before deleting the proxy.
+  virtual void Start() = 0;
+  // Must be called before deleting the proxy.
+  virtual void Stop() = 0;
 
   virtual void SetMutator(std::unique_ptr<LayerTreeMutator> mutator) = 0;
 
   virtual bool SupportsImplScrolling() const = 0;
 
   virtual void UpdateTopControlsState(TopControlsState constraints,
                                       TopControlsState current,
                                       bool animate) = 0;
 
   // Testing hooks
   virtual bool MainFrameWillHappenForTesting() = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROXY_H_