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

views/widget/widget.cc

Index: views/widget/widget.cc
===================================================================
--- views/widget/widget.cc	(revision 100773)
+++ views/widget/widget.cc	(working copy)
@@ -10,6 +10,7 @@
 #include "ui/base/l10n/l10n_font_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/compositor/compositor.h"
+#include "ui/gfx/compositor/layer.h"
 #include "views/controls/menu/menu_controller.h"
 #include "views/focus/focus_manager_factory.h"
 #include "views/focus/view_storage.h"
@@ -751,8 +752,8 @@
 }
 
 void Widget::CalculateOffsetToAncestorWithLayer(gfx::Point* offset,
-                                                View** ancestor) {
-  native_widget_->CalculateOffsetToAncestorWithLayer(offset, ancestor);
+                                                ui::Layer** layer_parent) {
+  native_widget_->CalculateOffsetToAncestorWithLayer(offset, layer_parent);
 }
 
 void Widget::NotifyAccessibilityEvent(
@@ -917,8 +918,7 @@
     return false;
 
   compositor->NotifyStart();
-  GetRootView()->PaintToLayer(dirty_region);
-  GetRootView()->PaintComposite();
+  GetRootView()->layer()->Draw();
   compositor->NotifyEnd();
   return true;
 }