Implement CWVWebView.scrollView.

ios/web_view/public/cwv_scroll_view_delegate.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_DELEGATE_H_
+#define IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_DELEGATE_H_
+
+#import <CoreGraphics/CoreGraphics.h>
+
+@class CWVScrollView;
+
+// Delegete for CWVScrollView. Has subset of methods of
+// UIScrollViewDelegate. See the document of

[michaeldo, 2017/05/01 18:49:53]

To match above suggestion, I recommend:

These methods are forwarded from the internal UIScrollViewDelegate. Please see
the <UIKit/UIScrollViewDelegate.h> documentation for details about the following
methods.

[Hiroshi Ichikawa, 2017/05/08 06:52:41]

Done.

+// UIScrollViewDelegate for the document of each method.
+CWV_EXPORT
+@protocol CWVScrollViewDelegate<NSObject>
+@optional
+- (void)scrollViewWillBeginDragging:(CWVScrollView*)scrollView;
+- (void)scrollViewWillEndDragging:(CWVScrollView*)scrollView
+                     withVelocity:(CGPoint)velocity
+              targetContentOffset:(inout CGPoint*)targetContentOffset;
+- (void)scrollViewDidScroll:(CWVScrollView*)scrollView;
+- (void)scrollViewDidEndDecelerating:(CWVScrollView*)scrollView;
+@end
+
+#endif  // IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_DELEGATE_H_