mus: Add watcher for all touch events.

ui/views/touch_event_watcher.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 UI_VIEWS_TOUCH_EVENT_WATCHER_H_
+#define UI_VIEWS_TOUCH_EVENT_WATCHER_H_
+
+#include "ui/views/views_export.h"
+
+namespace gfx {
+class Point;
+}
+
+namespace ui {
+class LocatedEvent;
+}
+
+namespace views {
+class Widget;
+
+class VIEWS_EXPORT TouchEventWatcher {

[sky, 2016/07/06 20:22:02]

Add description.

[riajiang, 2016/07/08 02:51:40]

Done.

+ public:
+  virtual ~TouchEventWatcher() {}

[sky, 2016/07/06 20:22:02]

move destructor to protected section to reinforce not owned.

[riajiang, 2016/07/08 02:51:40]

Done. Also changed this in PointerWatcher.

+
+  virtual void OnTouchEventObserved(const ui::LocatedEvent& event,
+                                    const gfx::Point& location_in_screen,
+                                    Widget* target) = 0;
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_TOUCH_EVENT_WATCHER_H_