Rework View Layer Draw() to use the Layer::DrawTree() method and the LayerDelegate.

aura/window.h

Index: aura/window.h
===================================================================
--- aura/window.h	(revision 100773)
+++ aura/window.h	(working copy)
@@ -87,9 +87,6 @@
   // TODO(beng): this is (obviously) feeble.
   void MoveChildToFront(Window* child);
 
-  // Draw the window and its children.
-  void DrawTree();
-
   // Tree operations.
   // TODO(beng): Child windows are currently not owned by the hierarchy. We
   //             should change this.
@@ -133,14 +130,11 @@
   // If SchedulePaint has been invoked on the Window the delegate is notified.
   void UpdateLayerCanvas();
 
-  // Draws the Window's contents.
-  void Draw();
-
   // Schedules a paint for the Window's entire bounds.
   void SchedulePaint();
 
   // Overridden from ui::LayerDelegate:
-  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+  virtual void OnPaintLayer(gfx::Canvas* canvas) OVERRIDE;
 
   WindowDelegate* delegate_;