Add Mojo IPC based input-device service.

ui/views/mus/window_manager_connection.h

Index: ui/views/mus/window_manager_connection.h
diff --git a/ui/views/mus/window_manager_connection.h b/ui/views/mus/window_manager_connection.h
index afcf368ab5653a8bafe7f8c9f834ede401a1f1fc..3c023461c801318b30a2080f94ccdc6cee6e0a38 100644
--- a/ui/views/mus/window_manager_connection.h
+++ b/ui/views/mus/window_manager_connection.h
@@ -7,10 +7,14 @@
 
 #include <stdint.h>
 
+#include <map>
 #include <memory>
+#include <string>
+#include <vector>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
+#include "components/mus/public/cpp/input_devices/input_device_client.h"
 #include "components/mus/public/cpp/window_tree_client_delegate.h"
 #include "services/shell/public/cpp/identity.h"
 #include "ui/views/mus/mus_export.h"
@@ -89,6 +93,8 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
   base::ObserverList<PointerWatcher, true> pointer_watchers_;
   bool created_device_data_manager_;
 
+  input_device::InputDeviceClient input_device_client_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowManagerConnection);
 };