(Set)IsOverridingUserAgent should be called on VisibleItem

ios/chrome/browser/tabs/tab.h

Index: ios/chrome/browser/tabs/tab.h
diff --git a/ios/chrome/browser/tabs/tab.h b/ios/chrome/browser/tabs/tab.h
index 163c827457e667e8de1a2aa9fe11a39a6add8bf8..158344756b1c7706907e6f2489a1ca576e7083d3 100644
--- a/ios/chrome/browser/tabs/tab.h
+++ b/ios/chrome/browser/tabs/tab.h
@@ -133,7 +133,11 @@ extern NSString* const kProxyPassthroughHeaderValue;
 @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;