Revert BrowserControlsOffsetManager changes

cc/input/browser_controls_offset_manager.h

 // Copyright 2016 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_INPUT_BROWSER_CONTROLS_OFFSET_MANAGER_H_
 #define CC_INPUT_BROWSER_CONTROLS_OFFSET_MANAGER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 62 matching lines @@
   BrowserControlsOffsetManager(BrowserControlsOffsetManagerClient* client,
                                float controls_show_threshold,
                                float controls_hide_threshold);
 
  private:
   void ResetAnimations();
   void SetupAnimation(AnimationDirection direction);
   void StartAnimationIfNecessary();
   bool IsAnimationComplete(float new_ratio);
   void ResetBaseline();
-  // Offset computation regardless of top or bottom control state.
-  float ContentOffsetInternal() const;
 
   // The client manages the lifecycle of this.
   BrowserControlsOffsetManagerClient* client_;
 
   base::TimeTicks animation_start_time_;
   float animation_start_value_;
   base::TimeTicks animation_stop_time_;
   float animation_stop_value_;
   AnimationDirection animation_direction_;
 
@@ skipping 14 matching lines @@
   float controls_hide_threshold_;
 
   bool pinch_gesture_active_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserControlsOffsetManager);
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_BROWSER_CONTROLS_OFFSET_MANAGER_H_