Pixel snap SVG's root border box to local transform [spv2]

third_party/WebKit/Source/core/paint/SVGRootPainter.h

 // Copyright 2014 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 SVGRootPainter_h
 #define SVGRootPainter_h
 
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 struct PaintInfo;
+class AffineTransform;
+class IntRect;
 class LayoutPoint;
 class LayoutSVGRoot;
 
 class SVGRootPainter {
     STACK_ALLOCATED();
 public:
     SVGRootPainter(const LayoutSVGRoot& layoutSVGRoot) : m_layoutSVGRoot(layoutSVGRoot) { }
 
     void paint(const PaintInfo&, const LayoutPoint&);
 
+    // The embedded SVG document uses an unsnapped viewport box for layout, while SVG root's border
+    // box ultimately gets snapped during paint. This translate/scale transform is applied to
+    // compensate the difference, in addition to applying the local to border box transform.
+    AffineTransform transformToPixelSnappedBorderBox(const LayoutPoint& paintOffset) const;
+
 private:
+    IntRect pixelSnappedSize(const LayoutPoint& paintOffset) const;
+
     const LayoutSVGRoot& m_layoutSVGRoot;
 };
 
 } // namespace blink
 
 #endif // SVGRootPainter_h