Add a basic demo mode browser test.

chrome/browser/chromeos/app_mode/kiosk_profile_loader.h

Index: chrome/browser/chromeos/app_mode/kiosk_profile_loader.h
diff --git a/chrome/browser/chromeos/app_mode/kiosk_profile_loader.h b/chrome/browser/chromeos/app_mode/kiosk_profile_loader.h
index 06b90291f004bf297414e27c0497a947c8613db5..edb6779533e8c620fd91bd2729393916773fbafe 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_profile_loader.h
+++ b/chrome/browser/chromeos/app_mode/kiosk_profile_loader.h
@@ -18,8 +18,6 @@ class Profile;
 
 namespace chromeos {
 
-class KioskAppManager;
-
 // KioskProfileLoader loads a special profile for a given app. It first
 // attempts to login for the app's generated user id. If the login is
 // successful, it prepares app profile then calls the delegate.
@@ -36,7 +34,7 @@ class KioskProfileLoader : public LoginPerformer::Delegate,
   };
 
   KioskProfileLoader(const std::string& app_user_id,
-                     bool force_ephemeral,
+                     bool force_guest,

[bartfab (slow), 2014/03/20 13:22:29]

Why is this being renamed from |ephemeral| to |guest|? It is not like you are
logging in as guest. You are still logging into a kiosk session, but using an
ephemeral mount.

[rkc, 2014/03/20 21:45:01]

Logging in a Kiosk account with an ephemeral mount is very different from using
a guest mount. A guest mount follows a code path that is designed to be used
without an owner, the ephemeral mount code path isn't. Additionally, according
to Cryptohome, a guest user _is logging in, we just bait and switch in the
callback from the mount changing the user back to the demo user.

All of these reasons put together make it a good idea to make sure that the user
of this method knows that we aren't just loading a normal Kiosk Mount as
Ephemeral but rather a guest mount, hence the rename.

[bartfab (slow), 2014/03/21 10:37:32]

Ugh. I had looked at ParallelAuthenticator::LoginAsKioskAccount(), saw that it
uses MountPublic() but missed the fact that it also uses MountGuest() sometimes.
This is a really awful hack. It should be fixed before any other follow-up fixes
are made. Guest is special on Chrome OS and it should be kept that way, instead
of mixing other features with it. Kiosk app sessions should use a different
mount command, which then takes an argument that tells cryptohomed whether to
mount as ephemeral or not.

[xiyuan, 2014/03/21 16:38:16]

From rkc@'s test, regular mount (i.e. Mount/MountPublic) does not work for demo
app because cryptohomed does not support doing regular mount before the machine
is owned. MountGuest is a workaround for that problem, given the time frame that
demo app is needed.

I am not sure what is the proper solution here though. We could add a call which
does MountGuest underhood but that does not make much difference.

[rkc, 2014/03/21 23:31:18]

What you described is what we used to do; but after speaking with drewry@, it
seems that the only way currently, or in the foreseeable future, for cryptohome
to be mounted without having an owner, is to use MountGuest. Once that changes,
I'd be happy to change the Chrome side code to match.

[bartfab (slow), 2014/03/25 12:52:54]

In that case, |force_guest| is still the wrong term. It used to be that you
either forced ephemeral or got ephemeral/non-ephemeral depending on policy. Now
you switch between guest and ephemeral/non-ephemeral. So this argument does not
force anything, it switches from a regular mount to a guest mount. It should be
called something like |use_guest_mount| then (here and elsewhere throughout the
CL).

[rkc, 2014/03/26 21:30:40]

Done.

                      Delegate* delegate);
 
   virtual ~KioskProfileLoader();
@@ -62,7 +60,7 @@ class KioskProfileLoader : public LoginPerformer::Delegate,
   virtual void OnProfilePrepared(Profile* profile) OVERRIDE;
 
   std::string user_id_;
-  bool force_ephemeral_;
+  bool force_guest_;
   Delegate* delegate_;
   scoped_ptr<CryptohomedChecker> cryptohomed_checker_;
   scoped_ptr<LoginPerformer> login_performer_;