Fixes crash in views/gtk when pressing space bar on a menu button.

views/controls/menu/menu_controller.cc

Index: views/controls/menu/menu_controller.cc
diff --git a/views/controls/menu/menu_controller.cc b/views/controls/menu/menu_controller.cc
index 2622523949f00f55f5b3020c53378084e84767df..22540e3a10a8c19544648dff2c13a2759cc1f781 100644
--- a/views/controls/menu/menu_controller.cc
+++ b/views/controls/menu/menu_controller.cc
@@ -822,8 +822,14 @@ bool MenuController::Dispatch(GdkEvent* event) {
     case GDK_KEY_PRESS: {
       base::KeyboardCode win_keycode =
           base::WindowsKeyCodeForGdkKeyCode(event->key.keyval);
+
       if (!OnKeyDown(win_keycode))
         return false;
+
+      // OnKeyDown may have set exit_type_.
+      if (exit_type_ != EXIT_NONE)
+        return false;
+
       guint32 keycode = gdk_keyval_to_unicode(event->key.keyval);
       if (keycode)
         return !SelectByChar(keycode);