Add KVO compliant title property to CWVWebView.

ios/web_view/public/cwv_web_view.h

 // Copyright 2014 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_WEB_VIEW_H_
 #define IOS_WEB_VIEW_PUBLIC_CWV_WEB_VIEW_H_
 
 #import <ChromeWebView/cwv_export.h>
 #import <UIKit/UIKit.h>
 
 @class CWVScrollView;
@@ skipping 30 matching lines @@
 
 // Whether or not this web view is loading a page.
 @property(nonatomic, readonly) BOOL isLoading;
 
 // The URL displayed in the url bar.
 @property(nonatomic, readonly) NSURL* visibleURL;
 
 // The URL of the current document.
 @property(nonatomic, readonly) NSURL* lastCommittedURL;
 
-// The current page title.
+// The current page title. KVO compliant.
 @property(nonatomic, readonly, copy) NSString* title;
 
 // Page loading progress from 0.0 to 1.0. KVO compliant.
 //
 // It is 0.0 initially before the first navigation starts. After a navigation
 // completes, it remains at 1.0 until a new navigation starts, at which point it
 // is reset to 0.0.
 @property(nonatomic, readonly) double estimatedProgress;
 
 // The scroll view associated with the web view.
@@ skipping 47 matching lines @@
 - (void)loadRequest:(NSURLRequest*)request;
 
 // Evaluates a JavaScript string.
 // The completion handler is invoked when script evaluation completes.
 - (void)evaluateJavaScript:(NSString*)javaScriptString
          completionHandler:(void (^)(id, NSError*))completionHandler;
 
 @end
 
 #endif  // IOS_WEB_VIEW_PUBLIC_CWV_WEB_VIEW_H_