Replace NinePieceImage.setMaskDefault with static method.

third_party/WebKit/Source/core/style/NinePieceImage.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2013 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 64 matching lines @@
  public:
   NinePieceImage();
   NinePieceImage(StyleImage*,
                  LengthBox image_slices,
                  bool fill,
                  const BorderImageLengthBox& border_slices,
                  const BorderImageLengthBox& outset,
                  ENinePieceImageRule horizontal_rule,
                  ENinePieceImageRule vertical_rule);
 
+  static NinePieceImage MaskDefaults() {
+    NinePieceImage image;
+    image.data_.Access()->image_slices = LengthBox(0);
+    image.data_.Access()->fill = true;
+    image.data_.Access()->border_slices = BorderImageLengthBox(Length(kAuto));
+    return image;
+  }
+
   bool operator==(const NinePieceImage& other) const {
     return data_ == other.data_;
   }
   bool operator!=(const NinePieceImage& other) const {
     return data_ != other.data_;
   }
 
   bool HasImage() const { return data_->image; }
   StyleImage* GetImage() const { return data_->image.Get(); }
   void SetImage(StyleImage* image) { data_.Access()->image = image; }
@@ skipping 43 matching lines @@
 
   void CopyOutsetFrom(const NinePieceImage& other) {
     data_.Access()->outset = other.data_->outset;
   }
 
   void CopyRepeatFrom(const NinePieceImage& other) {
     data_.Access()->horizontal_rule = other.data_->horizontal_rule;
     data_.Access()->vertical_rule = other.data_->vertical_rule;
   }
 
-  void SetMaskDefaults() {
-    data_.Access()->image_slices = LengthBox(0);
-    data_.Access()->fill = true;
-    data_.Access()->border_slices = BorderImageLengthBox(Length(kAuto));
-  }
-
   static LayoutUnit ComputeOutset(const BorderImageLength& outset_side,
                                   int border_side) {
     if (outset_side.IsNumber())
       return LayoutUnit(outset_side.Number() * border_side);
     return LayoutUnit(outset_side.length().Value());
   }
 
  private:
   DataRef<NinePieceImageData> data_;
 };
 
 }  // namespace blink
 
 #endif  // NinePieceImage_h