ash: Refactor touch hud drawing to ash/touch_hud as a separate component.

ui/views/controls/touch/touch_hud_drawer.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_CONTROLS_TOUCH_TOUCH_HUD_DRAWER_H_

[sky, 2016/07/06 16:31:30]

This code is specific to ash, and not something I see more places needing. Move
to ash/common/touch.

[riajiang, 2016/07/06 20:30:43]

The touch hud app would be under mash/ and needs to use this. Where would be the
best place to put it?

[sky, 2016/07/07 00:00:42]

Ah, I see now. How about ash/touch_hud, with it's own gn/gyp file that both
places use?

[riajiang, 2016/07/11 16:26:03]

Done.

+#define UI_VIEWS_CONTROLS_TOUCH_TOUCH_HUD_DRAWER_H_
+
+#include <map>
+
+#include "base/macros.h"
+#include "ui/views/views_export.h"
+
+namespace ash {
+class TouchHudProjectionTest;
+}
+
+namespace ui {
+class LocatedEvent;
+}
+
+namespace views {
+class TouchPointView;
+class Widget;
+
+class VIEWS_EXPORT TouchHudDrawer {

[sky, 2016/07/06 16:31:30]

Add description.

[riajiang, 2016/07/06 20:30:43]

Done.

+ public:
+   TouchHudDrawer();
+   ~TouchHudDrawer();
+
+  // Called to clear touch points and traces from the screen.
+  void Clear();
+
+  void HandleTouchEvent(const ui::LocatedEvent* event, Widget* parent_widget);

[sky, 2016/07/06 16:31:30]

Add description. In general please add comments for classes, member functions
and members.

[riajiang, 2016/07/06 20:30:43]

Done.

+
+ private:
+  friend class ash::TouchHudProjectionTest;
+
+  std::map<int, TouchPointView*> points_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchHudDrawer);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_CONTROLS_TOUCH_TOUCH_HUD_DRAWER_H_