services/ui: Create a proper component for the client-lib.

services/ui/public/cpp/input_event_handler.h

 // Copyright 2015 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 SERVICES_UI_PUBLIC_CPP_INPUT_EVENT_HANDLER_H_
 #define SERVICES_UI_PUBLIC_CPP_INPUT_EVENT_HANDLER_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
+#include "services/ui/public/cpp/ui_export.h"
 
 namespace ui {
 class Event;
 }
 
 namespace ui {
 
 class Window;
 
 namespace mojom {
 enum class EventResult;
 }
 
 // Responsible for processing input events for ui::Window.
-class InputEventHandler {
+class UI_EXPORT InputEventHandler {
  public:
   // The event handler can asynchronously ack the event by taking ownership of
   // the |ack_callback|. The callback takes an EventResult indicating if the
   // handler has consumed the event. If the handler does not take ownership of
   // the callback, then WindowTreeClient will ack the event as not consumed.
   virtual void OnWindowInputEvent(
       Window* target,
       const ui::Event& event,
       std::unique_ptr<base::Callback<void(mojom::EventResult)>>*
           ack_callback) = 0;
 
  protected:
   virtual ~InputEventHandler() {}
 };
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_PUBLIC_CPP_INPUT_EVENT_HANDLER_H_