Move SecurityInterstitialPage into component

components/security_interstitials/core/controller_client.h

Index: components/security_interstitials/core/controller_client.h
diff --git a/components/security_interstitials/core/controller_client.h b/components/security_interstitials/core/controller_client.h
index 8acbf35458d2165ac36d1044e76b0cb1bc7dd179..33d9cece49438ed842586b792cf8a538509ad5f8 100644
--- a/components/security_interstitials/core/controller_client.h
+++ b/components/security_interstitials/core/controller_client.h
@@ -89,9 +89,10 @@ class ControllerClient {
 
   virtual PrefService* GetPrefService() = 0;
 
+  virtual const std::string& GetApplicationLocale() const = 0;
+
  protected:
-  virtual const std::string& GetApplicationLocale() = 0;
-  virtual const std::string GetExtendedReportingPrefName() = 0;
+  virtual const std::string GetExtendedReportingPrefName() const = 0;
 
  private:
   std::unique_ptr<MetricsHelper> metrics_helper_;