Show an InfoBar when trying to start Packaged Apps from Metro mode.

apps/pref_names.cc

Index: apps/pref_names.cc
diff --git a/apps/pref_names.cc b/apps/pref_names.cc
index 15a33f936a52114979718cba639d60bbcb1db634..d4ac6fa5b03ceac871f31cec68c75d51d4726dd3 100644
--- a/apps/pref_names.cc
+++ b/apps/pref_names.cc
@@ -12,6 +12,15 @@ namespace prefs {
 const char kAppLauncherIsEnabled[] =
     "apps.app_launcher.should_show_apps_page";
 
+// If set, the user requested to launch the app with this extension id while
+// in Metro mode, and then relaunched to Desktop mode to start it.
+const char kAppLaunchForMetroRestart[] = "apps.app_launch_for_metro_restart";
+
+// Set with |kAppLaunchForMetroRestart|, the profile whose loading triggers
+// launch of the specified app when restarting Chrome in desktop mode.
+const char kAppLaunchForMetroRestartProfile[] =
+    "apps.app_launch_for_metro_restart_profile";
+
 }  // namespace prefs
 
 }  // namespace apps