Componentize the bad clock blocking page

chrome/browser/interstitials/security_interstitial_page.h

Index: chrome/browser/interstitials/security_interstitial_page.h
diff --git a/chrome/browser/interstitials/security_interstitial_page.h b/chrome/browser/interstitials/security_interstitial_page.h
index 914e096da12d12cf097e1fdffc5337b3b24d2836..471c1e2abd18cbab89b88f08f08d444cfaf18fd5 100644
--- a/chrome/browser/interstitials/security_interstitial_page.h
+++ b/chrome/browser/interstitials/security_interstitial_page.h
@@ -44,6 +44,10 @@ class SecurityInterstitialPage : public content::InterstitialPageDelegate {
   virtual void PopulateInterstitialStrings(
       base::DictionaryValue* load_time_data) = 0;
 
+  // Gives an opportunity for child classes to react to Show() having run. The
+  // interstitial_page_ will now have a value.
+  virtual void AfterShow() = 0;
+
   // InterstitialPageDelegate method:
   std::string GetHTMLContents() override;