WIP: <canvas> hit regions

Source/core/html/canvas/CanvasRenderingContext2D.h

Index: Source/core/html/canvas/CanvasRenderingContext2D.h
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.h b/Source/core/html/canvas/CanvasRenderingContext2D.h
index 27003eb1d581342e085a81783eebb72f8df90130..87e2237237d4f2ee96c1289fda893cb6d4d1bd13 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.h
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.h
@@ -49,9 +49,11 @@ namespace WebCore {
 
 class CanvasImageSource;
 class CanvasGradient;
+class CanvasHitRegion;
+class CanvasHitRegionManager;
 class CanvasPattern;
 class CanvasStyle;
-class Path2D;
+struct DecodedHitRegionOptions;
 class Element;
 class ExceptionState;
 class FloatRect;
@@ -61,6 +63,7 @@ class HTMLImageElement;
 class HTMLVideoElement;
 class ImageBitmap;
 class ImageData;
+class Path2D;
 class TextMetrics;
 
 typedef WillBeHeapHashMap<String, RefPtrWillBeMember<MutableStylePropertySet> > MutableStylePropertyMap;
@@ -224,6 +227,11 @@ public:
 
     PassRefPtr<Canvas2DContextAttributes> getContextAttributes() const;
 
+    void addHitRegion(ExceptionState&);
+    void addHitRegion(const Dictionary& options, ExceptionState&);
+    void removeHitRegion(const String& id);
+    CanvasHitRegion* hitRegionAtPoint(const LayoutPoint&);
+
     void drawFocusIfNeeded(Element*);
     void drawFocusIfNeeded(Path2D*, Element*);
     bool drawCustomFocusRing(Element*);
@@ -330,6 +338,8 @@ private:
     template<class T> void fullCanvasCompositedStroke(const T&);
     template<class T> void fullCanvasCompositedDrawImage(T*, const FloatRect&, const FloatRect&, CompositeOperator);
 
+    void addHitRegionInternal(const DecodedHitRegionOptions&, ExceptionState&);
+
     void drawFocusIfNeededInternal(const Path&, Element*);
     bool focusRingCallIsValid(const Path&, Element*);
     void updateFocusRingAccessibility(const Path&, Element*);
@@ -344,6 +354,7 @@ private:
     virtual blink::WebLayer* platformLayer() const OVERRIDE;
 
     WillBeHeapVector<OwnPtrWillBeMember<State> > m_stateStack;
+    OwnPtrWillBeMember<CanvasHitRegionManager> m_hitRegionManager;
     bool m_usesCSSCompatibilityParseMode;
     bool m_hasAlpha;
     bool m_isContextLost;