Simplify security_interstitials::ControllerClient and other related classes

ios/chrome/browser/interstitials/ios_security_interstitial_page.h

Index: ios/chrome/browser/interstitials/ios_security_interstitial_page.h
diff --git a/ios/chrome/browser/interstitials/ios_security_interstitial_page.h b/ios/chrome/browser/interstitials/ios_security_interstitial_page.h
index 128f833188de0236295d6f2ccfd12b31f1dc7dd3..1a508e5449a79c057b89668d0bd32968f153be9a 100644
--- a/ios/chrome/browser/interstitials/ios_security_interstitial_page.h
+++ b/ios/chrome/browser/interstitials/ios_security_interstitial_page.h
@@ -12,16 +12,10 @@
 #include "ios/web/public/interstitials/web_interstitial_delegate.h"
 #include "url/gurl.h"
 
-class IOSChromeControllerClient;
-
 namespace base {
 class DictionaryValue;
 }
 
-namespace security_interstitials {
-class MetricsHelper;
-}
-
 namespace web {
 class WebInterstitial;
 class WebState;