Implement CWVWebView.scrollView.

ios/web_view/internal/cwv_scroll_view.mm

Index: ios/web_view/internal/cwv_scroll_view.mm
diff --git a/ios/web_view/internal/cwv_scroll_view.mm b/ios/web_view/internal/cwv_scroll_view.mm
new file mode 100644
index 0000000000000000000000000000000000000000..5b35ac3846b396cb8142c4a8c86374ad26c5a37f
--- /dev/null
+++ b/ios/web_view/internal/cwv_scroll_view.mm
@@ -0,0 +1,102 @@
+// 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.
+
+#import "ios/web_view/public/cwv_scroll_view.h"
+
+#import "ios/web/public/web_state/ui/crw_web_view_scroll_view_proxy.h"
+#import "ios/web_view/internal/cwv_scroll_view_internal.h"
+#import "ios/web_view/public/cwv_scroll_view_delegate.h"
+
+@interface CWVScrollView ()<CRWWebViewScrollViewProxyObserver>
+@end
+
+@implementation CWVScrollView
+
+@synthesize delegate = _delegate;
+@synthesize proxy = _proxy;
+
+- (void)setProxy:(CRWWebViewScrollViewProxy*)proxy {
+  if (_proxy) {

[Eugene But (OOO till 7-30), 2017/04/26 19:11:31]

There is no need for this check, calling a method on nil is fine

[Hiroshi Ichikawa, 2017/04/27 02:30:10]

Done.

+    [_proxy removeObserver:self];
+  }
+  _proxy = proxy;
+  if (_proxy) {
+    [_proxy addObserver:self];

[Eugene But (OOO till 7-30), 2017/04/26 19:11:31]

ditto

[Hiroshi Ichikawa, 2017/04/27 02:30:10]

Done.

+  }
+}
+
+- (CGPoint)contentOffset {
+  return _proxy.contentOffset;
+}
+
+- (void)setContentOffset:(CGPoint)contentOffset {
+  _proxy.contentOffset = contentOffset;
+}
+
+- (CGRect)frame {
+  return _proxy.frame;
+}
+
+- (CGRect)bounds {
+  return {_proxy.contentOffset, _proxy.frame.size};
+}
+
+- (CGSize)contentSize {
+  return _proxy.contentSize;
+}
+
+- (BOOL)isDragging {
+  return _proxy.dragging;
+}
+
+- (void)addGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer {
+  [_proxy addGestureRecognizer:gestureRecognizer];
+}
+
+- (UIEdgeInsets)contentInset {
+  return _proxy.contentInset;
+}
+
+- (void)setContentInset:(UIEdgeInsets)contentInset {
+  _proxy.contentInset = contentInset;
+}
+
+#pragma mark - CRWWebViewScrollViewObserver
+
+- (void)webViewScrollViewWillBeginDragging:
+    (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
+  if ([_delegate
+          respondsToSelector:@selector(webViewScrollViewWillBeginDragging:)]) {
+    [_delegate scrollViewWillBeginDragging:self];
+  }
+}
+- (void)webViewScrollViewWillEndDragging:
+            (CRWWebViewScrollViewProxy*)webViewScrollViewProxy
+                            withVelocity:(CGPoint)velocity
+                     targetContentOffset:(inout CGPoint*)targetContentOffset {
+  if ([_delegate respondsToSelector:@selector

[Eugene But (OOO till 7-30), 2017/04/26 19:11:31]

Do you want to create a local variable for selector to improve the formatting?

[Hiroshi Ichikawa, 2017/04/27 02:30:10]

Done.

+                 (webViewScrollViewWillEndDragging:withVelocity
+                                                     :targetContentOffset:)]) {
+    [_delegate scrollViewWillEndDragging:self
+                            withVelocity:velocity
+                     targetContentOffset:targetContentOffset];
+  }
+}
+
+- (void)webViewScrollViewDidScroll:
+    (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
+  if ([_delegate respondsToSelector:@selector(scrollViewDidScroll:)]) {
+    [_delegate scrollViewDidScroll:self];
+  }
+}
+
+- (void)webViewScrollViewDidEndDecelerating:
+    (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
+  if ([_delegate
+          respondsToSelector:@selector(webViewScrollViewDidEndDecelerating:)]) {

[Eugene But (OOO till 7-30), 2017/04/26 19:11:31]

ditto

[Hiroshi Ichikawa, 2017/04/27 02:30:11]

Done.

+    [_delegate scrollViewDidEndDecelerating:self];
+  }
+}
+
+@end