Implement ephemeral users

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 2f4f5e6013295e7c4cb99a5630022cb7c3c5473f..c3adf4cde0219ccffae1b9a8213b0cca0295cfb1 100644
--- a/chrome/browser/chromeos/login/user_manager.h
+++ b/chrome/browser/chromeos/login/user_manager.h
@@ -58,12 +58,12 @@ class UserManager {
 
   virtual ~UserManager();
 
-  // Returns a list of the users who have logged into this device previously.
-  // It is sorted in order of recency, with most recent at the beginning.
+  // Returns a list of users who have logged into this device previously. This
+  // is sorted by last login date with the most recent user at the beginning.
   virtual const UserList& GetUsers() const = 0;
 
-  // Indicates that a user with the given email has just logged in.
-  // The persistent list will be updated accordingly.
+  // Indicates that a user with the given email has just logged in. The
+  // persistent list is updated accordingly if the user is not ephemeral.
   virtual void UserLoggedIn(const std::string& email) = 0;
 
   // Indicates that user just logged on as the demo user.
@@ -82,10 +82,12 @@ class UserManager {
   // picture.
   virtual void RemoveUserFromList(const std::string& email) = 0;
 
-  // Returns true if given user has logged into the device before.
+  // Returns true if a user with the given email address is found in the
+  // persistent list or currently logged in as ephemeral.
   virtual bool IsKnownUser(const std::string& email) const = 0;
 
-  // Returns a user with given email or |NULL| if no such user exists.
+  // Returns the user with the given email address if found in the persistent
+  // list or currently logged in as ephemeral. Returns |NULL| otherwise.
   virtual const User* FindUser(const std::string& email) const = 0;
 
   // Returns the logged-in user.
@@ -146,6 +148,9 @@ class UserManager {
   // Returns true if current user is not existing one (hasn't signed in before).
   virtual bool IsCurrentUserNew() const = 0;
 
+  // Returns true if the current user is ephemeral.
+  virtual bool IsCurrentUserEphemeral() const = 0;
+
   // Returns true if user is signed in.
   virtual bool IsUserLoggedIn() const = 0;