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

chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc

Index: chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc
diff --git a/chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc b/chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc
index fb88489e5f6d06277563baf38fd8776311779cdc..6ed0af3693cffc44bac6fa20d76364a61b90f127 100644
--- a/chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc
+++ b/chrome/browser/ui/toolbar/wrench_menu_model_chromeos.cc
@@ -72,11 +72,10 @@ void WrenchMenuModel::Build() {
 
   AddSeparator();
 
-  AddItemWithStringId(IDC_LOCK_SCREEN, IDS_LOCK_SCREEN);
-
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kGuestSession)) {
     AddItemWithStringId(IDC_EXIT, IDS_EXIT_GUEST_MODE);
   } else {
+    AddItemWithStringId(IDC_LOCK_SCREEN, IDS_LOCK_SCREEN);
     AddItemWithStringId(IDC_EXIT, IDS_SIGN_OUT);
   }
 }