chromeos: makes mus send keyevents to display root when nothing has focus

ash/mus/accelerators/accelerator_controller_registrar.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_MUS_ACCELERATORS_ACCELERATOR_CONTROLLER_REGISTRAR_H_
 #define ASH_MUS_ACCELERATORS_ACCELERATOR_CONTROLLER_REGISTRAR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 54 matching lines @@
   // is just a temporary solution and we should remove these once we have a
   // proper solution.
   void RegisterWindowCycleAccelerators();
   bool HandleWindowCycleAccelerator(const ui::Accelerator& accelerator);
 
   // The flow of accelerators in ash is:
   // . wm::AcceleratorFilter() sees events first as it's a pre-target handler.
   // . AcceleratorFilter forwards to its delegate, which indirectly is
   //   implemented by AcceleratorRouter.
   // . AcceleratorRouter may early out, if not it calls through to
-  //   AcceleratorController. This stop may stop propagation entirely.
+  //   AcceleratorController. This may stop propagation entirely.
   // . If focus is on a Widget, then NativeWidgetAura gets the key event, calls
   //   to Widget::OnKeyEvent(), which calls to FocusManager::OnKeyEvent(), which
   //   calls to AshFocusManagerFactory::Delegate::ProcessAccelerator() finally
   //   ending up in AcceleratorController::Process().
   // . OTOH if focus is on a content, then
   //   RenderWidgetHostViewAura::OnKeyEvent() is called and may end up consuming
   //   the event.
   //
   // To get this behavior for mash we register accelerators for both pre and
   // post. Pre gives the behavior of AcceleratorRouter and post that of
@@ skipping 28 matching lines @@
   // Maps from accelerator to the two ids registered for it.
   std::map<ui::Accelerator, Ids> accelerator_to_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorControllerRegistrar);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_ACCELERATORS_ACCELERATOR_CONTROLLER_REGISTRAR_H_