(Set)IsOverridingUserAgent should be called on VisibleItem

ios/chrome/browser/tabs/tab.h

 // Copyright 2012 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_CHROME_BROWSER_TABS_TAB_H_
 #define IOS_CHROME_BROWSER_TABS_TAB_H_
 
 #import <UIKit/UIKit.h>
 
 #include <memory>
@@ skipping 115 matching lines @@
 @property(nonatomic, readonly) web::WebState* webState;
 
 @property(nonatomic, readonly) CRWWebController* webController;
 @property(nonatomic, readonly) PasswordController* passwordController;
 @property(nonatomic, readonly) BOOL canGoBack;
 @property(nonatomic, readonly) BOOL canGoForward;
 @property(nonatomic, assign) id<TabDelegate> delegate;
 @property(nonatomic, assign) id<TabHeadersDelegate> tabHeadersDelegate;
 @property(nonatomic, assign) id<TabSnapshottingDelegate>
     tabSnapshottingDelegate;
-@property(nonatomic, readonly) BOOL useDesktopUserAgent;
+
+// Whether or not desktop user agent is used for the currently loaded page.

[Eugene But (OOO till 7-30), 2017/02/23 00:54:23]

Please update the comment, because visibleItem does not represent "currently
loaded page".

[liaoyuke, 2017/02/23 01:10:14]

Done.

+@property(nonatomic, readonly, getter=isUsingDesktopUserAgent)
+    BOOL usesDesktopUserAgent;
+
 @property(nonatomic, assign) id<StoreKitLauncher> storeKitLauncher;
 @property(nonatomic, assign) id<FullScreenControllerDelegate>
     fullScreenControllerDelegate;
 @property(nonatomic, readonly)
     OverscrollActionsController* overscrollActionsController;
 @property(nonatomic, assign) id<OverscrollActionsControllerDelegate>
     overscrollActionsControllerDelegate;
 @property(nonatomic, assign) id<SnapshotOverlayProvider>
     snapshotOverlayProvider;
 
@@ skipping 189 matching lines @@
 
 // Called when this tab is hidden.
 - (void)wasHidden;
 
 // Evaluates U2F result.
 - (void)evaluateU2FResultFromURL:(const GURL&)url;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_H_