Implement request mobile site.

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>
 #include <vector>
 
 #import "components/signin/ios/browser/manage_accounts_delegate.h"
 #include "ios/net/request_tracker.h"
+#include "ios/web/public/user_agent.h"
 #import "ios/web/public/web_state/ui/crw_web_delegate.h"
 #include "ui/base/page_transition_types.h"
 
 @class AutofillController;
 @class AutoReloadBridge;
 @class CastController;
 @class CRWWebController;
 @class ExternalAppLauncher;
 @class FormInputAccessoryViewController;
 @class FullScreenController;
@@ skipping 206 matching lines @@
 // Returns the infobars::InfoBarManager object for this tab.
 - (infobars::InfoBarManager*)infoBarManager;
 
 // 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;
 
-// Remove the UIWebView and reload the current url.  Used by request desktop
-// so the updated user agent is used.
-- (void)reloadForDesktopUserAgent;
+// Removes the web view and loads the original url of the last non-redirect item

[kkhorimoto, 2017/04/11 01:09:41]

We aren't removing the web view anymore, are we?  Can't we just set the
|customUserAgent| property of the WKWebView?

[Eugene But (OOO till 7-30), 2017/04/11 02:11:56]

In any case Tab should not make any assumptions about implementation details or
even that WKWebView is used.

[liaoyuke, 2017/04/11 18:27:20]

That is a very good point! Thanks!

[liaoyuke, 2017/04/11 18:27:20]

Set |customUserAgent| property requires re-factoring a few files to use
UserAgentType, so I wanted to save it to a separate CL.

+// (including non-history items).  Used by request desktop/mobile site so the
+// updated user agent is used.
+- (void)reloadWithUserAgentType:(web::UserAgentType)userAgentType;
 
 // 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 41 matching lines @@
 // Evaluates U2F result.
 - (void)evaluateU2FResultFromURL:(const GURL&)url;
 
 // Cancels prerendering. It is an error to call this on anything except a
 // prerender tab (where |isPrerenderTab| is set to YES).
 - (void)discardPrerender;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_H_