[ObjC ARC] Converts parts of ios/web/webstate to ARC.

ios/web/public/web_state/ui/crw_web_view_content_view.h

 // Copyright 2015 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_PUBLIC_WEB_STATE_UI_CRW_WEB_VIEW_CONTENT_VIEW_H_
 #define IOS_WEB_PUBLIC_WEB_STATE_UI_CRW_WEB_VIEW_CONTENT_VIEW_H_
 
 #import "ios/web/public/web_state/ui/crw_content_view.h"
 
 // Wraps a web vew in a CRWContentView.
 @interface CRWWebViewContentView : CRWContentView
 
 // The webView passed to |-initWithWebView|.
-@property(nonatomic, retain, readonly) UIView* webView;
+@property(nonatomic, strong, readonly) UIView* webView;
 
 // Initializes the CRWWebViewContentView to display |webView|.
 - (instancetype)initWithWebView:(UIView*)webView
                      scrollView:(UIScrollView*)scrollView
     NS_DESIGNATED_INITIALIZER;
 
 // Available only for testing.
 - (instancetype)initForTesting NS_DESIGNATED_INITIALIZER;
 
 // CRWWebViewContentViews should be initialized via |-initWithWebView:
 // scrollView:|.
 - (instancetype)initWithCoder:(NSCoder*)decoder NS_UNAVAILABLE;
 - (instancetype)initWithFrame:(CGRect)frame NS_UNAVAILABLE;
 
 @end
 
 #endif  // IOS_WEB_PUBLIC_WEB_STATE_UI_CRW_WEB_VIEW_CONTENT_VIEW_H_