Pass a ui::PaintContext from ui::Layer to layer delegates.

ash/drag_drop/drag_drop_controller.cc

 // Copyright (c) 2012 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.
 
 #include "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "base/bind.h"
@@ skipping 87 matching lines @@
   bool ShouldDescendIntoChildForEventHandling(
       aura::Window* child,
       const gfx::Point& location) override {
     return true;
   }
   bool CanFocus() override { return true; }
   void OnCaptureLost() override {
     if (drag_drop_controller_->IsDragDropInProgress())
       drag_drop_controller_->DragCancel();
   }
-  void OnPaint(gfx::Canvas* canvas) override {}
+  void OnPaint(const ui::PaintContext& context) override {}
   void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
   void OnWindowDestroying(aura::Window* window) override {}
   void OnWindowDestroyed(aura::Window* window) override {}
   void OnWindowTargetVisibilityChanged(bool visible) override {}
   bool HasHitTestMask() const override { return true; }
   void GetHitTestMask(gfx::Path* mask) const override {
     DCHECK(mask->isEmpty());
   }
 
  private:
@@ skipping 442 matching lines @@
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so delete
   // the pointer with a local variable to avoid double free.
   scoped_ptr<ash::DragDropTracker> holder = drag_drop_tracker_.Pass();
 }
 
 }  // namespace ash