cros: Add app mode restrictions.

ash/accelerators/accelerator_controller.h

Index: ash/accelerators/accelerator_controller.h
diff --git a/ash/accelerators/accelerator_controller.h b/ash/accelerators/accelerator_controller.h
index 468a5bffea6f17263e80648d296dd4b1e3560d10..53ed723d1e0ac991c0e9eb459979b107e6212e38 100644
--- a/ash/accelerators/accelerator_controller.h
+++ b/ash/accelerators/accelerator_controller.h
@@ -156,6 +156,8 @@ class ASH_EXPORT AcceleratorController : public ui::AcceleratorTarget {
   std::set<int> reserved_actions_;
   // Actions which will not be repeated while holding the accelerator key.
   std::set<int> nonrepeatable_actions_;
+  // Actions allowed in app mode.
+  std::set<int> actions_allowed_in_app_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorController);
 };