Implement CWVWebView.scrollView.

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. Has subset of methods of
+// UIScrollView. 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.
+//
+// See the document of UIScrollView for the document of each

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

Please re-wrap comments.

Please replace "See the document of UIScrollView for the document of each
method." with

"These methods are forwarded to the internal UIScrollView. Please see the
<UIKit/UIScrollView.h> documentation for details about the following methods."

With this explanation, you can probably remove "Has subset of methods of
UIScrollView." from earlier in the comment.

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

Done.

+// method.
+//
+// TODO: Add nullability annotations.

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

Please add a bug number and update TODO formatting.

// TODO(crbug.com/######): Something that needs doing.

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

Done.

+CWV_EXPORT
+@interface CWVScrollView : NSObject
+
+@property(nonatomic, readonly) CGRect frame;

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

Can you confirm that |frame| needs to be exposed?

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

Hm it may not be necessary. Let me remove it for now. I may add back later if I
find it is needed.

+@property(nonatomic, readonly) CGRect bounds;
+@property(nonatomic) CGPoint contentOffset;
+@property(nonatomic, weak) id<CWVScrollViewDelegate> delegate;
+@property(nonatomic, readonly, getter=isDragging) BOOL dragging;
+- (void)addGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer;

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

Please move method after all properties.

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

Done.

+
+// 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;
+
+@end
+
+#endif  // IOS_WEB_VIEW_PUBLIC_CWV_SCROLL_VIEW_H_