Make sure to display an errors that occur during the chrome sign in process

chrome/browser/ui/sync/one_click_signin_helper.h

Index: chrome/browser/ui/sync/one_click_signin_helper.h
diff --git a/chrome/browser/ui/sync/one_click_signin_helper.h b/chrome/browser/ui/sync/one_click_signin_helper.h
index 9bc0eab8cce866b40f464535bef18bf5aabb9576..8e12f591a6541bffd73c7cb4fe9465d715c9e0f8 100644
--- a/chrome/browser/ui/sync/one_click_signin_helper.h
+++ b/chrome/browser/ui/sync/one_click_signin_helper.h
@@ -50,6 +50,12 @@ class OneClickSigninHelper
     IGNORE_REQUEST
   };
 
+  // Argument to CanOffer().
+  enum CanOfferFor {
+    CAN_OFFER_FOR_ALL,
+    CAN_OFFER_FOR_INTERSTITAL_ONLY,
+  };
+
   virtual ~OneClickSigninHelper();
 
   // Called only by tests to associate information with a given request.
@@ -57,14 +63,23 @@ class OneClickSigninHelper
                                              const std::string& email);
 
   // Returns true if the one-click signin feature can be offered at this time.
-  // It can be offered if the contents is not in an incognito window.  If
-  // |check_connected| is true, then the profile is checked to see if it's
+  // If |email| is not empty, then the profile is checked to see if it's
   // already connected to a google account or if the user has already rejected
   // one-click sign-in with this email, in which cases a one click signin
   // should not be offered.
+  //
+  // If |can_offer_for| is |CAN_OFFER_FOR_INTERSTITAL_ONLY|, then only do the
+  // checks that would affect the interstitial page.  Otherwise, do the checks
+  // that would affect the interstitial and the explicit sign ins.
+  //
+  // Returns in |error_message_id| an explanation as a string resource ID for
+  // why one-clicked cannot be offered.  |error_message_id| is valid only if
+  // the return value is false.  If no explanation is needed, |error_message_id|
+  // may be null.
   static bool CanOffer(content::WebContents* web_contents,
+                       CanOfferFor can_offer_for,
                        const std::string& email,
-                       bool check_connected);
+                       int* error_message_id);
 
   // Returns true if the one-click signin feature can be offered at this time.
   // It can be offered if the io_data is not in an incognito window and if the
@@ -127,6 +142,11 @@ class OneClickSigninHelper
                                   int child_id,
                                   int route_id);
 
+  void RedirectToNTP();
+
+  // Clear all data member of the helper, except for the error.
+  void CleanTransientState();
+
   // content::WebContentsObserver overrides.
   virtual void DidNavigateAnyFrame(
       const content::LoadCommittedDetails& details,
@@ -145,6 +165,8 @@ class OneClickSigninHelper
   std::string password_;
   AutoAccept auto_accept_;
   SyncPromoUI::Source source_;
+  std::string error_message_;
+
   scoped_ptr<SigninTracker> signin_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(OneClickSigninHelper);