Enable ChromeVox on the OOBE screens when using the keyboard shortcut.

R=dmazzoni
BUG=chromium-os:14804
TEST=Press ctrl+alt+z on the OOBE screen to enable accessibility.  Continue to the Terms of service page.  Press tab to move focus to the DOM view.  Press shift + space + down to navigate the EULA.  Ensure that it's spoken.

Review URL: http://codereview.chromium.org/7609001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@96136 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/accessibility_util.cc

@@ -88,6 +88,7 @@ void EnableAccessibility(bool enabled, WebUI* login_web_ui) {
 
   g_browser_process->local_state()->SetBoolean(
       prefs::kAccessibilityEnabled, enabled);
+  g_browser_process->local_state()->ScheduleSavePersistentPrefs();
   ExtensionAccessibilityEventRouter::GetInstance()->
       SetAccessibilityEnabled(enabled);