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

ash/touch/touch_hud_projection.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// 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 ASH_TOUCH_TOUCH_HUD_PROJECTION_H_
 #define ASH_TOUCH_TOUCH_HUD_PROJECTION_H_
 
 #include <map>
 
 #include "ash/touch/touch_observer_hud.h"
 #include "base/macros.h"
 
 namespace ash {
-class TouchPointView;
+class TouchHudRenderer;
 
 // A heads-up display to show active touch points on the screen. As a derivative
 // of TouchObserverHUD, objects of this class manage their own lifetime.
 class TouchHudProjection : public TouchObserverHUD {
  public:
   explicit TouchHudProjection(aura::Window* initial_root);
 
   // Overriden from TouchObserverHUD.
   void Clear() override;
 
  private:
   friend class TouchHudProjectionTest;
 
   ~TouchHudProjection() override;
 
   // Overriden from TouchObserverHUD.
   void OnTouchEvent(ui::TouchEvent* event) override;
   void SetHudForRootWindowController(RootWindowController* controller) override;
   void UnsetHudForRootWindowController(
       RootWindowController* controller) override;
 
-  std::map<int, TouchPointView*> points_;
+  // TouchHudRenderer draws out the touch points
+  std::unique_ptr<ash::TouchHudRenderer> touch_hud_renderer_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchHudProjection);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TOUCH_TOUCH_HUD_PROJECTION_H_