Add custom interstitial for captive portals.

chrome/browser/ssl/ssl_blocking_page.h

Index: chrome/browser/ssl/ssl_blocking_page.h
diff --git a/chrome/browser/ssl/ssl_blocking_page.h b/chrome/browser/ssl/ssl_blocking_page.h
index 062c3b99df422f3e03ed7c6d48a01808d0643d96..9f13141038c87539715e8f621e0037550d35b1b6 100644
--- a/chrome/browser/ssl/ssl_blocking_page.h
+++ b/chrome/browser/ssl/ssl_blocking_page.h
@@ -43,8 +43,16 @@ class SSLBlockingPage : public SecurityInterstitialPage {
   };
 
   enum SSLBlockingPageOptionsMask {
+    // Indicates whether or not the user could (assuming perfect knowledge)
+    // successfully override the error and still get the security guarantees
+    // of TLS.
     OVERRIDABLE = 1 << 0,
+    // Indicates whether or not the site the user is trying to connect to has
+    // requested strict enforcement of certificate validation (e.g. with HTTP
+    // Strict-Transport-Security).
     STRICT_ENFORCEMENT = 1 << 1,
+    // Indicates whether a user decision had been previously made but the
+    // decision has expired.
     EXPIRED_BUT_PREVIOUSLY_ALLOWED = 1 << 2
   };
 
@@ -74,6 +82,8 @@ class SSLBlockingPage : public SecurityInterstitialPage {
   static void SetExtraInfo(base::DictionaryValue* strings,
                            const std::vector<base::string16>& extra_info);
 
+  static bool IsOverridable(int options_mask);
+
  protected:
   // InterstitialPageDelegate implementation.
   void CommandReceived(const std::string& command) override;