Add a basic demo mode browser test.

chrome/browser/chromeos/login/parallel_authenticator.cc

Index: chrome/browser/chromeos/login/parallel_authenticator.cc
diff --git a/chrome/browser/chromeos/login/parallel_authenticator.cc b/chrome/browser/chromeos/login/parallel_authenticator.cc
index 29ffe01df4da276ab7900e54bca1ab2e094bd509..82ac885b6e2b3520d8802abbf468463380f09b1c 100644
--- a/chrome/browser/chromeos/login/parallel_authenticator.cc
+++ b/chrome/browser/chromeos/login/parallel_authenticator.cc
@@ -110,6 +110,23 @@ void MountGuest(AuthAttemptState* attempt,
                  resolver));
 }
 
+// Calls cryptohome's mount method for guest and also get the user hash from
+// cryptohome.
+void MountGuestAndGetHash(AuthAttemptState* attempt,
+                          scoped_refptr<ParallelAuthenticator> resolver) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  cryptohome::AsyncMethodCaller::GetInstance()->AsyncMountGuest(

[bartfab (slow), 2014/03/27 14:13:29]

The AuthAttemptState constructor sets username_hash_obtained_ = true, meaning
that the user id hash is already known and there is no need to wait for it.
Since you want to retrieve the hash from cryptohome, you need to make sure that
ParallelAuthenticator waits for the result by invoking
attempt->UsernameHashRequested(); before making any cryptohome calls.

See line 85, where Mount() does exactly that.

[rkc, 2014/03/27 21:43:10]

Done.

+      base::Bind(&TriggerResolveWithLoginTimeMarker,
+                 "CryptohomeMount-End",
+                 attempt,
+                 resolver));
+  cryptohome::AsyncMethodCaller::GetInstance()->AsyncGetSanitizedUsername(
+      attempt->user_context.username,
+      base::Bind(&TriggerResolveHash,
+                 attempt,
+                 resolver));
+}
+
 // Calls cryptohome's MountPublic method
 void MountPublic(AuthAttemptState* attempt,
                  scoped_refptr<ParallelAuthenticator> resolver,
@@ -346,11 +363,12 @@ void ParallelAuthenticator::LoginAsPublicAccount(const std::string& username) {
 }
 
 void ParallelAuthenticator::LoginAsKioskAccount(
-    const std::string& app_user_id, bool force_ephemeral) {
+    const std::string& app_user_id,
+    bool use_guest_mount) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  std::string user_id =
-      force_ephemeral ? UserManager::kGuestUserName : app_user_id;
+  const std::string user_id =
+      use_guest_mount ? UserManager::kGuestUserName : app_user_id;
   current_state_.reset(new AuthAttemptState(
       UserContext(user_id,
                   std::string(),  // password
@@ -361,14 +379,14 @@ void ParallelAuthenticator::LoginAsKioskAccount(
       false));
 
   remove_user_data_on_failure_ = true;
-  if (!force_ephemeral) {
+  if (!use_guest_mount) {
     MountPublic(current_state_.get(),
           scoped_refptr<ParallelAuthenticator>(this),
           cryptohome::CREATE_IF_MISSING);
   } else {
     ephemeral_mount_attempted_ = true;
-    MountGuest(current_state_.get(),
-               scoped_refptr<ParallelAuthenticator>(this));
+    MountGuestAndGetHash(current_state_.get(),
+                         scoped_refptr<ParallelAuthenticator>(this));
   }
 }