Implement basic parts of hit regions on canvas2d.

Source/core/html/canvas/CanvasRenderingContext2D.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 105 matching lines @@
     [RaisesException] void drawImage(HTMLCanvasElement canvas, unrestricted float x, unrestricted float y);
     [RaisesException] void drawImage(HTMLCanvasElement canvas, unrestricted float x, unrestricted float y, unrestricted float width, unrestricted float height);
     [RaisesException] void drawImage(HTMLCanvasElement canvas, unrestricted float sx, unrestricted float sy, unrestricted float sw, unrestricted float sh, unrestricted float dx, unrestricted float dy, unrestricted float dw, unrestricted float dh);
     [RaisesException] void drawImage(HTMLVideoElement video, unrestricted float x, unrestricted float y);
     [RaisesException] void drawImage(HTMLVideoElement video, unrestricted float x, unrestricted float y, unrestricted float width, unrestricted float height);
     [RaisesException] void drawImage(HTMLVideoElement video, unrestricted float sx, unrestricted float sy, unrestricted float sw, unrestricted float sh, unrestricted float dx, unrestricted float dy, unrestricted float dw, unrestricted float dh);
     [RuntimeEnabled=ExperimentalCanvasFeatures, RaisesException] void drawImage(ImageBitmap imageBitmap, unrestricted float x, unrestricted float y);
     [RuntimeEnabled=ExperimentalCanvasFeatures, RaisesException] void drawImage(ImageBitmap imageBitmap, unrestricted float x, unrestricted float y, unrestricted float width, unrestricted float height);
     [RuntimeEnabled=ExperimentalCanvasFeatures, RaisesException] void drawImage(ImageBitmap imageBitmap, unrestricted float sx, unrestricted float sy, unrestricted float sw, unrestricted float sh, unrestricted float dx, unrestricted float dy, unrestricted float dw, unrestricted float dh);
 
+    // hit regions
+    // FIXME: Blink does not currently support WebIDL dictionary definitions.
+    // See http://crbug.com/321462
+    [RuntimeEnabled=ExperimentalCanvasFeatures, RaisesException] void addHitRegion(optional Dictionary options);
+    [RuntimeEnabled=ExperimentalCanvasFeatures] void removeHitRegion(DOMString id);
+    [RuntimeEnabled=ExperimentalCanvasFeatures] void clearHitRegions();
+
     // pixel manipulation
     ImageData createImageData(ImageData imagedata);
     [RaisesException] ImageData createImageData(float sw, float sh);
     [RaisesException] ImageData getImageData(float sx, float sy, float sw, float sh);
     void putImageData(ImageData imagedata, float dx, float dy);
     void putImageData(ImageData imagedata, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight);
 
     // Context state
     // Should be merged with WebGL counterpart in CanvasRenderingContext, once no-longer experimental
     [RuntimeEnabled=ExperimentalCanvasFeatures] boolean isContextLost();
@@ skipping 37 matching lines @@
     [MeasureAs=CanvasRenderingContext2DDrawImageFromRect] void drawImageFromRect(
         HTMLImageElement? image, optional unrestricted float sx, optional unrestricted float sy, optional unrestricted float sw, optional unrestricted float sh,
         optional unrestricted float dx, optional unrestricted float dy, optional unrestricted float dw, optional unrestricted float dh, optional DOMString compositeOperation);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(unrestricted float width, unrestricted float height, unrestricted float blur, optional DOMString color, optional unrestricted float alpha);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(unrestricted float width, unrestricted float height, unrestricted float blur, unrestricted float grayLevel, optional unrestricted float alpha);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(unrestricted float width, unrestricted float height, unrestricted float blur, unrestricted float r, unrestricted float g, unrestricted float b, unrestricted float a);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(unrestricted float width, unrestricted float height, unrestricted float blur, unrestricted float c, unrestricted float m, unrestricted float y, unrestricted float k, unrestricted float a);
 };
 
 CanvasRenderingContext2D implements CanvasPathMethods;