Simplify security_interstitials::ControllerClient and other related classes

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 2aced84ce84fba50fe5cecb95dcd86ba19eaccc1..fb9ed3483c2fdf268cc55d24c34d46662353fa04 100644
--- a/components/security_interstitials/core/controller_client.h
+++ b/components/security_interstitials/core/controller_client.h
@@ -55,7 +55,7 @@ enum SecurityInterstitialCommands {
 // by the JavaScript error page.
 class ControllerClient {
  public:
-  ControllerClient();
+  explicit ControllerClient(std::unique_ptr<MetricsHelper> metrics_helper);
   virtual ~ControllerClient();
 
   // Handle the user's reporting preferences.
@@ -76,7 +76,6 @@ class ControllerClient {
   virtual void Reload() = 0;
 
   MetricsHelper* metrics_helper() const;
-  void set_metrics_helper(std::unique_ptr<MetricsHelper> metrics_helper);
 
   virtual void OpenUrlInCurrentTab(const GURL& url) = 0;