Update prefservice only if it is available.

components/security_interstitials/content/security_interstitial_page.h

 // Copyright 2014 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 COMPONENTS_SECURITY_INTERSTITIALS_CONTENT_SECURITY_INTERSTITIAL_PAGE_H_
 #define COMPONENTS_SECURITY_INTERSTITIALS_CONTENT_SECURITY_INTERSTITIAL_PAGE_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 46 matching lines @@
   // InterstitialPageDelegate method:
   std::string GetHTMLContents() override;
 
   // Returns the formatted host name for the request url.
   base::string16 GetFormattedHostName() const;
 
   content::InterstitialPage* interstitial_page() const;
   content::WebContents* web_contents() const;
   GURL request_url() const;
 
-  // Returns the boolean value of the given |pref|.
-  bool IsPrefEnabled(const char* pref);
-
   SecurityInterstitialControllerClient* controller();
 
   MetricsHelper* metrics_helper();
 
  private:
   // The WebContents with which this interstitial page is
   // associated. Not available in ~SecurityInterstitialPage, since it
   // can be destroyed before this class is destroyed.
   content::WebContents* web_contents_;
   const GURL request_url_;
   // Once shown, |interstitial_page| takes ownership of this
   // SecurityInterstitialPage instance.
   content::InterstitialPage* interstitial_page_;
   // Whether the interstitial should create a view.
   bool create_view_;
   // For subclasses that don't have their own ControllerClients yet.
   std::unique_ptr<SecurityInterstitialControllerClient> controller_;
 
   std::unique_ptr<MetricsHelper> metrics_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(SecurityInterstitialPage);
 };
 
 }  // security_interstitials
 
 #endif  // COMPONENTS_SECURITY_INTERSTITIALS_CONTENT_SECURITY_INTERSTITIAL_PAGE_H_