Implement basic parts of hit regions on canvas2d.

Source/platform/graphics/Path.cpp

 /*
  * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
  *                     2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ skipping 33 matching lines @@
 Path::Path()
     : m_path()
 {
 }
 
 Path::Path(const Path& other)
 {
     m_path = SkPath(other.m_path);
 }
 
+Path::Path(const SkPath& skPath)
+{
+    m_path = skPath;
+}
+
 Path::~Path()
 {
 }
 
 Path& Path::operator=(const Path& other)
 {
     m_path = SkPath(other.m_path);
     return *this;
 }
 
@@ skipping 411 matching lines @@
 void Path::addPath(const Path& src, const AffineTransform& transform)
 {
     m_path.addPath(src.skPath(), affineTransformToSkMatrix(transform));
 }
 
 void Path::translate(const FloatSize& size)
 {
     m_path.offset(WebCoreFloatToSkScalar(size.width()), WebCoreFloatToSkScalar(size.height()));
 }
 
+bool Path::subtractPath(const Path& other)
+{
+    return Op(m_path, other.m_path, kDifference_PathOp, &m_path);
+}
+
+bool Path::intersectPath(const Path& other)
+{
+    return Op(m_path, other.m_path, kIntersect_PathOp, &m_path);
+}
+
 bool Path::unionPath(const Path& other)
 {
     return Op(m_path, other.m_path, kUnion_PathOp, &m_path);
 }
 
 #if !ASSERT_DISABLED
 bool ellipseIsRenderable(float startAngle, float endAngle)
 {
     return (std::abs(endAngle - startAngle) < twoPiFloat)
         || WebCoreFloatNearlyEqual(std::abs(endAngle - startAngle), twoPiFloat);
 }
 #endif
 
 }