Revert of Replace requirePageReconstruction with setCustomUserAgent

ios/web/web_state/ui/crw_web_controller.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_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_
 #define IOS_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/web/net/crw_request_tracker_delegate.h"
@@ skipping 173 matching lines @@
 // Navigates to the item at the given |index|.
 - (void)goToItemAtIndex:(int)index;
 
 // Executes |script| in the web view, registering user interaction.
 - (void)executeUserJavaScript:(NSString*)script
             completionHandler:(web::JavaScriptResultBlock)completion;
 
 // Dismisses the soft keyboard.
 - (void)dismissKeyboard;
 
+// Requires that the next load rebuild the UIWebView. This is expensive, and
+// should be used only in the case where something has changed that UIWebView
+// only checks on creation, such that the whole object needs to be rebuilt.
+// TODO(stuartmorgan): Merge this and reinitializeWebViewAndReload:. They are
+// currently subtly different in terms of implementation, but are for
+// fundamentally the same purpose.
+- (void)requirePageReconstruction;
+
 - (void)reinitializeWebViewAndReload:(BOOL)reload;
 
 // Requires that the next display reload the page, using a placeholder while
 // loading. This could be used, e.g., to handle a crash in a WebController that
 // is not currently visible.
 // TODO(stuartmorgan): When revisiting the methods above, revisit this as well.
 - (void)requirePageReload;
 
 // Show overlay, don't reload web page. Used when the view will be
 // visible only briefly (e.g., tablet side swipe).
@@ skipping 90 matching lines @@
 
 // Acts on a single message from the JS object, parsed from JSON into a
 // DictionaryValue. Returns NO if the format for the message was invalid.
 - (BOOL)respondToMessage:(base::DictionaryValue*)crwMessage
        userIsInteracting:(BOOL)userIsInteracting
                originURL:(const GURL&)originURL;
 
 @end
 
 #endif  // IOS_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_