Move SecurityInterstitialPage into component

ios/chrome/browser/interstitials/ios_chrome_controller_client.h

Index: ios/chrome/browser/interstitials/ios_chrome_controller_client.h
diff --git a/ios/chrome/browser/interstitials/ios_chrome_controller_client.h b/ios/chrome/browser/interstitials/ios_chrome_controller_client.h
index f92aa7f8ca332c8237dd2f026beec75fe150b4ef..53f0eba8cc08961288d6ce5b7dac3299042478dc 100644
--- a/ios/chrome/browser/interstitials/ios_chrome_controller_client.h
+++ b/ios/chrome/browser/interstitials/ios_chrome_controller_client.h
@@ -41,9 +41,9 @@ class IOSChromeControllerClient
   void Proceed() override;
   void Reload() override;
   void OpenUrlInCurrentTab(const GURL& url) override;
-  const std::string& GetApplicationLocale() override;
-  PrefService* GetPrefService() override;
-  const std::string GetExtendedReportingPrefName() override;
+  const std::string& GetApplicationLocale() const override;
+  PrefService* GetPrefService() const override;

[Eugene But (OOO till 7-30), 2016/12/28 19:02:52]

Should |PrefService*| be also const? What if ControllerClient owns PrefService*
object?

[Jialiu Lin, 2016/12/28 19:40:32]

We cannot do "const PrefService* GetPrefService() const" here ... Since, certain
user actions on interstitial need to modify PrefService (e.g. check/uncheck
extended reporting opt-in checkbox) 

[Eugene But (OOO till 7-30), 2016/12/28 20:01:34]

nit: If that's the case then is it fair to make |GetPrefService| method const?
It was not const before, which is reasonable, because returning non-const
PrefService* allows changing the state of ControllerClient.

[Jialiu Lin, 2016/12/28 20:13:40]

You're right. Changed GetPrefService() back to non-const method. 

+  const std::string GetExtendedReportingPrefName() const override;
 
   web::WebState* web_state_;
   web::WebInterstitial* web_interstitial_;