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

ui/views/widget/native_widget_aura.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_
 #define UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_
 
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/aura/client/focus_change_observer.h"
@@ skipping 136 matching lines @@
   void OnBoundsChanged(const gfx::Rect& old_bounds,
                        const gfx::Rect& new_bounds) override;
   ui::TextInputClient* GetFocusedTextInputClient() override;
   gfx::NativeCursor GetCursor(const gfx::Point& point) override;
   int GetNonClientComponent(const gfx::Point& point) const override;
   bool ShouldDescendIntoChildForEventHandling(
       aura::Window* child,
       const gfx::Point& location) override;
   bool CanFocus() override;
   void OnCaptureLost() override;
-  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;
   void GetHitTestMask(gfx::Path* mask) const override;
 
   // Overridden from aura::WindowObserver:
   void OnWindowPropertyChanged(aura::Window* window,
                                const void* key,
@@ skipping 62 matching lines @@
   // The following factory is used for calls to close the NativeWidgetAura
   // instance.
   base::WeakPtrFactory<NativeWidgetAura> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetAura);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_