Canvas2d: Make the intersection computation O(1) instead of O(n) in ClipList.

third_party/WebKit/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 32 matching lines @@
 Path::Path()
     : m_path()
 {
 }
 
 Path::Path(const Path& other)
 {
     m_path = SkPath(other.m_path);
 }
 
+Path::Path(const SkPath& other)
+{
+    m_path = other;
+}
+
 Path::~Path()
 {
 }
 
 Path& Path::operator=(const Path& other)
 {
     m_path = SkPath(other.m_path);
     return *this;
 }
 
@@ skipping 438 matching lines @@
 bool Path::subtractPath(const Path& other)
 {
     return Op(m_path, other.m_path, kDifference_SkPathOp, &m_path);
 }
 
 bool Path::unionPath(const Path& other)
 {
     return Op(m_path, other.m_path, kUnion_SkPathOp, &m_path);
 }
 
+bool Path::intersectPath(const Path& other)
+{
+    return Op(m_path, other.m_path, kIntersect_SkPathOp, &m_path);
+}
+
 #if ENABLE(ASSERT)
 bool ellipseIsRenderable(float startAngle, float endAngle)
 {
     return (std::abs(endAngle - startAngle) < twoPiFloat)
         || WebCoreFloatNearlyEqual(std::abs(endAngle - startAngle), twoPiFloat);
 }
 #endif
 
 } // namespace blink