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

ash/display/cursor_window_controller.cc

Index: ash/display/cursor_window_controller.cc
diff --git a/ash/display/cursor_window_controller.cc b/ash/display/cursor_window_controller.cc
index 5f9ebed13eb29b23104332014aca9f0893e70ee3..f7f2b1035eceb97e6e4208fd341d6e5002442200 100644
--- a/ash/display/cursor_window_controller.cc
+++ b/ash/display/cursor_window_controller.cc
@@ -16,6 +16,7 @@
 #include "ui/base/hit_test.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/dip_util.h"
+#include "ui/compositor/paint_context.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/image/image_skia.h"
@@ -47,8 +48,8 @@ class CursorWindowDelegate : public aura::WindowDelegate {
   }
   bool CanFocus() override { return false; }
   void OnCaptureLost() override {}
-  void OnPaint(gfx::Canvas* canvas) override {
-    canvas->DrawImageInt(cursor_image_, 0, 0);
+  void OnPaint(const ui::PaintContext& context) override {
+    context.canvas()->DrawImageInt(cursor_image_, 0, 0);
   }
   void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
   void OnWindowDestroying(aura::Window* window) override {}