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

ash/touch/touch_hud_projection.h

Index: ash/touch/touch_hud_projection.h
diff --git a/ash/touch/touch_hud_projection.h b/ash/touch/touch_hud_projection.h
index ec0f8a24e57ee18a665427587f802e3c0078e58d..d5708d09136cac3f10e68ff9808f771dc1a941fc 100644
--- a/ash/touch/touch_hud_projection.h
+++ b/ash/touch/touch_hud_projection.h
@@ -11,7 +11,7 @@
 #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.
@@ -33,7 +33,8 @@ class TouchHudProjection : public TouchObserverHUD {
   void UnsetHudForRootWindowController(
       RootWindowController* controller) override;
 
-  std::map<int, TouchPointView*> points_;
+  // TouchHudRenderer draws out the touch points.
+  std::unique_ptr<TouchHudRenderer> touch_hud_renderer_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchHudProjection);
 };