Perform online reauth when password is changed for a locked profile.

chrome/browser/ui/user_manager.h

Index: chrome/browser/ui/user_manager.h
diff --git a/chrome/browser/ui/user_manager.h b/chrome/browser/ui/user_manager.h
index 4e0d21715c91b7a12447ca4aa797d0dfa4596fb3..c0c77e4d664349ad605cf2943ce65f4bd7deed06 100644
--- a/chrome/browser/ui/user_manager.h
+++ b/chrome/browser/ui/user_manager.h
@@ -32,6 +32,14 @@ class UserManager {
   // To be called once the User Manager's contents are showing.
   static void OnUserManagerShown();
 
+  // Shows a dialog where the user can re-authenticate when their profile is
+  // not yet open.  This is called from the user manager when a profile is
+  // locked and it has detected that the user's password has changed since the
+  // profile was locked.
+  static void ShowReauthDialog(content::BrowserContext* browser_context,
+                               const std::string& email,
+                               size_t profile_index);

[sky, 2015/07/23 16:56:04]

Is it common to pass around an index like this as identity? Might the index
shift around while the dialog is up? Say a profile is removed?

[Alexei Svitkine (slow), 2015/07/23 21:49:33]

I share this concern. I think it can be a problem if we keep it as a member of a
class like a dialog. Either it would need to listen to notifications on changes
- or use the profile name string for the identifier instead.

[Roger Tawa OOO till Jul 10th, 2015/07/24 16:15:12]

I redid this code to no longer need an index.

+
   // TODO(noms): Figure out if this size can be computed dynamically or adjusted
   // for smaller screens.
   static const int kWindowWidth = 800;