Address races in UserImageManagerImpl

chrome/browser/chromeos/login/user_manager.h

Index: chrome/browser/chromeos/login/user_manager.h
diff --git a/chrome/browser/chromeos/login/user_manager.h b/chrome/browser/chromeos/login/user_manager.h
index 415ef7d26a31dbd96a5b182d4fd05c3df03b4479..85b06c057bd8c23ecccd9d04c7215f3c87710ba6 100644
--- a/chrome/browser/chromeos/login/user_manager.h
+++ b/chrome/browser/chromeos/login/user_manager.h
@@ -174,6 +174,11 @@ class UserManager {
   // list or currently logged in as ephemeral. Returns |NULL| otherwise.
   virtual const User* FindUser(const std::string& user_id) const = 0;
 
+  // Returns the user with the given user id if found in the persistent
+  // list or currently logged in as ephemeral. Returns |NULL| otherwise.
+  // Same as FindUser but returns non-const pointer to User object.
+  virtual User* FindUserAndModify(const std::string& user_id) = 0;
+
   // Returns the logged-in user.
   // TODO(nkostylev): Deprecate this call, move clients to GetActiveUser().
   // http://crbug.com/230852