mac: Add overscroll animator slider

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 "base/mac/scoped_nsobject.h"
+#include "base/memory/scoped_ptr.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.
+  scoped_ptr<overscroll_animator::WebContentsPaintObserver> observer_;
+}
+@end
+
+#endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_SLIDER_MAC_H_