Remove unreferenced content/browser/web_contents/web_contents_view_overscroll_ files.

content/browser/web_contents/web_contents_view_overscroll_animator_slider_mac.h

-// Copyright 2014 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 CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_SLIDER_MAC_H_
-#define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_SLIDER_MAC_H_
-
-#import <Cocoa/Cocoa.h>
-
-#include <memory>
-
-#include "base/mac/scoped_nsobject.h"
-#include "content/browser/web_contents/web_contents_view_overscroll_animator_mac.h"
-
-namespace overscroll_animator {
-class WebContentsPaintObserver;
-}  // namespace overscroll_animator
-
-@interface OverscrollAnimatorSliderView
-    : NSView<WebContentsOverscrollAnimator> {
-  // This container view holds the RenderWidgetHost's NativeViews. Most of the
-  // time, its frame in screen coordinates is the same as SliderView's frame in
-  // screen coordinates. During an overscroll animation, it may temporarily be
-  // relocated, but it will return to its original position after the overscroll
-  // animation is finished.
-  base::scoped_nsobject<NSView> middleView_;
-
-  // This view is a sibling of middleView_, and is guaranteed to live below it.
-  // Most of the time, it is hidden. During a backwards overscroll animation,
-  // middleView_ is slid to the right, and bottomView_ peeks out from the
-  // original position of middleView_.
-  base::scoped_nsobject<NSImageView> bottomView_;
-
-  // This view is a sibling of middleView_, and is guaranteed to live above it.
-  // Most of the time, it is hidden. During a forwards overscroll animation,
-  // topView_ is slid to the left from off screen, its final position exactly
-  // covering middleView_.
-  base::scoped_nsobject<NSImageView> topView_;
-
-  // The direction of the current overscroll animation. This property has no
-  // meaning when inOverscroll_ is false.
-  content::OverscrollAnimatorDirection direction_;
-
-  // Indicates that this view is completing or cancelling the overscroll. This
-  // animation cannot be cancelled.
-  BOOL animating_;
-
-  // Reflects whether this view is in the process of handling an overscroll.
-  BOOL inOverscroll_;
-
-  // The most recent value passed to -updateOverscrollProgress:.
-  CGFloat progress_;
-
-  // An observer that reports the first non-empty paint of a WebContents. This
-  // is used when completing an overscroll animation.
-  std::unique_ptr<overscroll_animator::WebContentsPaintObserver> observer_;
-}
-@end
-
-#endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_SLIDER_MAC_H_