Implement CWVWebView.scrollView.

ios/web_view/public/cwv_scroll_view_delegate.h

Index: ios/web_view/public/cwv_scroll_view_delegate.h
diff --git a/ios/web_view/public/cwv_scroll_view_delegate.h b/ios/web_view/public/cwv_scroll_view_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..d5eee58a9d2cd2d004918d3dfcb6c48cb143bdc6
--- /dev/null
+++ b/ios/web_view/public/cwv_scroll_view_delegate.h
@@ -0,0 +1,28 @@
+// 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.
+//
+// These methods are forwarded from the internal UIScrollViewDelegate. Please
+// see the <UIKit/UIScrollViewDelegate.h> documentation for details about the
+// following methods.
+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_