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

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index f07d50d4b5428571f5575d5d44a724934e0c6e3c..00813e06a7008c5c9b30f9e8ecb867a8c72aaecc 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -1111,7 +1111,7 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   void UpdateChildLayerBounds(const gfx::Vector2d& offset);
 
   // Overridden from ui::LayerDelegate:
-  void OnPaintLayer(gfx::Canvas* canvas) override;
+  void OnPaintLayer(const ui::PaintContext& context) override;
   void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override;
   void OnDeviceScaleFactorChanged(float device_scale_factor) override;
   base::Closure PrepareForLayerBoundsChange() override;