[iOS] Add Request Mobile Site cell to tools menu

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 263 matching lines @@
 
 // Whether the content of the current tab is compatible with reader mode.
 - (BOOL)canSwitchToReaderMode;
 
 // Asks the tab to enter into reader mode, presenting a streamlined view of the
 // current content.
 - (void)switchToReaderMode;
 
 // Update internal state to use the desktop user agent. Must call
 // -reloadWebViewAndURL for changes to take effect.
-- (void)enableDesktopUserAgent;

[liaoyuke, 2017/02/23 22:17:17]

I found "enable" confusing because it is already used in the tools menu to
represent if the "Request Desktop Site" is clickable.

+- (void)activateDesktopUserAgent;
 
-// Remove the UIWebView and reload the current url.  Used by request desktop
-// so the updated user agent is used.
-- (void)reloadForDesktopUserAgent;
+// Update internal state to use the mobile user agent. Must call
+// -reloadWebViewAndURL for changes to take effect.
+- (void)activateMobileUserAgent;
+
+// Remove the web view and reload the current url.  Used by request desktop or
+// mobile site, so the updated user agent is used.
+- (void)reloadForUpdatedUserAgent;
 
 // Ensures the toolbar visibility matches |visible|.
 - (void)updateFullscreenWithToolbarVisible:(BOOL)visible;
 
 // Returns a snapshot of the current page, backed by disk so it can be purged
 // and reloaded easily. The snapshot may be in memory, saved on disk or not
 // present at all.
 // 1) If the snapshot is in memory |block| will be called synchronously with
 // the existing image.
 // 2) If the snapshot is saven on disk |block| will be called asynchronously
@@ skipping 40 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_