Refactors keyboard related code so mash can use a keyboard

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index a8d4e7591fd6e494f140c89c0842261f927311ec..680f8a1e62897e6b72595947626c726485105e81 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -98,6 +98,7 @@ class FirstRunHelper;
 class FocusCycler;
 class GPUSupport;
 class HighContrastController;
+class KeyboardUI;
 class KeyboardUMAEventFilter;
 class LastWindowClosedLogoutReminder;
 class LocaleNotificationController;
@@ -564,6 +565,10 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
     return is_touch_hud_projection_enabled_;
   }
 
+  KeyboardUI* keyboard_ui() { return keyboard_ui_.get(); }
+
+  bool in_mus() const { return in_mus_; }
+
 #if defined(OS_CHROMEOS)
   // Creates instance of FirstRunHelper. Caller is responsible for deleting
   // returned object.
@@ -766,6 +771,10 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 
   base::SequencedWorkerPool* blocking_pool_;
 
+  bool in_mus_ = false;
+
+  scoped_ptr<KeyboardUI> keyboard_ui_;
+
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };