Add more methods to CWVScrollView and CWVScrollViewDelegate.

ios/web_view/public/cwv_scroll_view.h

 // Copyright 2017 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 IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_H_
 #define IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_H_
 
 #import <ChromeWebView/cwv_export.h>
 #import <CoreGraphics/CoreGraphics.h>
 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
 @protocol CWVScrollViewDelegate;
 
 // Scroll view inside the web view. This is not a subclass of UIScrollView
 // because the underlying //ios/web API only exposes a proxy object of the
 // scroll view, not the raw UIScrollView.
 //
 // These methods are forwarded to the internal UIScrollView. Please see the
 // <UIKit/UIScrollView.h> documentation for details about the following methods.
 //
 // TODO(crbug.com/719323): Add nullability annotations.
 CWV_EXPORT
 @interface CWVScrollView : NSObject
 
 @property(nonatomic, readonly) CGRect bounds;
 @property(nonatomic) CGPoint contentOffset;
+@property(nonatomic) UIEdgeInsets scrollIndicatorInsets;
 @property(nonatomic, weak) id<CWVScrollViewDelegate> delegate;
+@property(nonatomic, readonly, getter=isDecelerating) BOOL decelerating;
 @property(nonatomic, readonly, getter=isDragging) BOOL dragging;
+@property(nonatomic, readonly) UIPanGestureRecognizer* panGestureRecognizer;
 
 // KVO compliant.
 @property(nonatomic, readonly) CGSize contentSize;
 
 // Be careful when using this property. There's a bug with the
 // underlying WKWebView where the web view does not respect contentInsets
 // properly when laying out content and calculating innerHeight for Javascript.
 // Content is laid out based on the entire height of the web view rather than
 // the height between the top and bottom insets.
 // https://bugs.webkit.org/show_bug.cgi?id=134230
 // rdar://23584409 (not available on Open Radar)
 @property(nonatomic) UIEdgeInsets contentInset;
 
+- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated;
 - (void)addGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer;
+- (void)removeGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer;
 
 @end
 
 #endif  // IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_H_