Implement CWVWebView.scrollView.

ios/web_view/internal/cwv_scroll_view_internal.h

Index: ios/web_view/internal/cwv_scroll_view_internal.h
diff --git a/ios/web_view/internal/cwv_scroll_view_internal.h b/ios/web_view/internal/cwv_scroll_view_internal.h
new file mode 100644
index 0000000000000000000000000000000000000000..5328719a788b74e33523d59517565655feb891fc
--- /dev/null
+++ b/ios/web_view/internal/cwv_scroll_view_internal.h
@@ -0,0 +1,22 @@
+// 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_INTERNAL_CWV_SCROLL_VIEW_INTERNAL_H_
+#define IOS_WEB_VIEW_INTERNAL_CWV_SCROLL_VIEW_INTERNAL_H_
+
+#import <ChromeWebView/cwv_export.h>
+#import <Foundation/Foundation.h>
+
+#import "ios/web_view/public/cwv_scroll_view.h"
+
+@class CRWWebViewScrollViewProxy;
+
+@interface CWVScrollView ()
+
+// Operations to this scroll view are delegated to this proxy.
+@property(nonatomic, weak, readwrite) CRWWebViewScrollViewProxy* proxy;
+
+@end
+
+#endif  // IOS_WEB_VIEW_INTERNAL_CWV_SCROLL_VIEW_INTERNAL_H_