Remove lock screen item from menu and disable screen lock on guest session.

chrome/browser/chromeos/login/screen_locker.cc

Index: chrome/browser/chromeos/login/screen_locker.cc
diff --git a/chrome/browser/chromeos/login/screen_locker.cc b/chrome/browser/chromeos/login/screen_locker.cc
index 6a86ae495bd83f2d1e11d3aa8a72a17ba9cddc3c..8b441299bd7ed13c4713bf9c85f7937e5940702d 100644
--- a/chrome/browser/chromeos/login/screen_locker.cc
+++ b/chrome/browser/chromeos/login/screen_locker.cc
@@ -351,6 +351,15 @@ void ScreenLocker::Show() {
   UserMetrics::RecordAction(UserMetricsAction("ScreenLocker_Show"));
   DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
 
+  // Check whether the currently logged in user is a guest account and if so,
+  // refuse to lock the screen (crosbug.com/23764).
+  // TODO(flackr): We can allow lock screen for guest accounts when
+  // unlock_on_input is supported by the WebUI screen locker.
+  if (UserManager::Get()->logged_in_user().email().empty()) {
+    VLOG(1) << "Show: Refusing to lock screen for guest account.";

[achuithb, 2011/12/07 18:46:02]

Could you please change this to DVLOG? And change the other VLOGs in this
function too? 

[flackr, 2011/12/07 19:05:55]

Done.

+    return;
+  }
+
   // Exit fullscreen.
   Browser* browser = BrowserList::GetLastActive();
   // browser can be NULL if we receive a lock request before the first browser