Implement basic parts of hit regions on canvas2d.

Source/platform/graphics/Path.cpp

Index: Source/platform/graphics/Path.cpp
diff --git a/Source/platform/graphics/Path.cpp b/Source/platform/graphics/Path.cpp
index 1fb35c058621dc9bf19e4bf90f3aaed9956b8a72..4d778531a885fa7048cd97c4ad286e183541a494 100644
--- a/Source/platform/graphics/Path.cpp
+++ b/Source/platform/graphics/Path.cpp
@@ -51,6 +51,11 @@ Path::Path(const Path& other)
     m_path = SkPath(other.m_path);
 }
 
+Path::Path(const SkPath& skPath)
+{
+    m_path = skPath;
+}
+
 Path::~Path()
 {
 }
@@ -482,6 +487,16 @@ 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);