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

third_party/WebKit/Source/modules/canvas2d/ClipList.h

Index: third_party/WebKit/Source/modules/canvas2d/ClipList.h
diff --git a/third_party/WebKit/Source/modules/canvas2d/ClipList.h b/third_party/WebKit/Source/modules/canvas2d/ClipList.h
index 591eb5fb05e0339f1d0a62f7e7c2773b7af52373..a15510beb55322fd20f6f19a8d416bf9c20886d0 100644
--- a/third_party/WebKit/Source/modules/canvas2d/ClipList.h
+++ b/third_party/WebKit/Source/modules/canvas2d/ClipList.h
@@ -25,7 +25,7 @@ public:
 
     void clipPath(const SkPath&, AntiAliasingMode, const SkMatrix&);
     void playback(SkCanvas*) const;
-    SkPath intersectPathWithClip(const SkPath&) const;
+    const SkPath& getCurrentClipPath() const;
 
 private:
 
@@ -41,6 +41,7 @@ private:
     static const size_t cInlineClipOpCapacity = 4;
 
     WTF::Vector<ClipOp, cInlineClipOpCapacity> m_clipList;
+    SkPath m_currentClipPath;
 };
 
 } // namespace blink