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 aebff2c9e53f1d883523ae156e1a5af1122f4373..42f9990ee2fa656f260e095d6ecdfee8e7d822bd 100644
--- a/components/security_interstitials/core/controller_client.h
+++ b/components/security_interstitials/core/controller_client.h
@@ -56,7 +56,7 @@ 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.
@@ -78,7 +78,6 @@ 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;