keep only one typedef for the native drawing context

skia/ext/platform_device.h

Index: skia/ext/platform_device.h
diff --git a/skia/ext/platform_device.h b/skia/ext/platform_device.h
index 177c730ff1a06080caa61e84270e4f09956a4a93..fe210003156935ff9cafbf95dddb808bf411cc96 100644
--- a/skia/ext/platform_device.h
+++ b/skia/ext/platform_device.h
@@ -65,8 +65,8 @@ class SK_API PlatformDevice {
   // The DC that corresponds to the bitmap, used for GDI operations drawing
   // into the bitmap. This is possibly heavyweight, so it should be existant
   // only during one pass of rendering.
-  virtual PlatformSurface BeginPlatformPaint(const SkMatrix& transform,
-                                             const SkIRect& clip_bounds);
+  virtual NativeDrawingContext BeginPlatformPaint(const SkMatrix& transform,
+                                                  const SkIRect& clip_bounds);
 
   friend class ScopedPlatformPaint;
 };