Implement basic parts of hit regions on canvas2d.

Source/core/core.gypi

 {
     'includes': [
       'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/Animation.idl',
             'animation/AnimationEffect.idl',
             'animation/AnimationPlayer.idl',
@@ skipping 450 matching lines @@
             'events/EventListener.idl',
             'events/NavigatorEvents.idl',
             'frame/NavigatorCPU.idl',
             'frame/NavigatorID.idl',
             'frame/NavigatorLanguage.idl',
             'frame/NavigatorOnLine.idl',
             'frame/WindowBase64.idl',
             'frame/WindowEventHandlers.idl',
             'frame/WindowTimers.idl',
             'html/canvas/CanvasPathMethods.idl',
+            'html/canvas/MouseEventHitRegion.idl',
             'html/canvas/WebGLRenderingContextBase.idl',
             'page/WindowPagePopup.idl',
             'svg/SVGDocument.idl',
             'svg/SVGFilterPrimitiveStandardAttributes.idl',
             'svg/SVGFitToViewBox.idl',
             'svg/SVGTests.idl',
             'svg/SVGURIReference.idl',
             'svg/SVGZoomAndPan.idl',
             'workers/AbstractWorker.idl',
             'xml/DocumentXPathEvaluator.idl',
@@ skipping 2049 matching lines @@
             'html/canvas/DataView.cpp',
             'html/canvas/DataView.h',
             'html/canvas/EXTBlendMinMax.cpp',
             'html/canvas/EXTBlendMinMax.h',
             'html/canvas/EXTFragDepth.cpp',
             'html/canvas/EXTFragDepth.h',
             'html/canvas/EXTShaderTextureLOD.cpp',
             'html/canvas/EXTShaderTextureLOD.h',
             'html/canvas/EXTTextureFilterAnisotropic.cpp',
             'html/canvas/EXTTextureFilterAnisotropic.h',
+            'html/canvas/HitRegion.cpp',
+            'html/canvas/HitRegion.h',
+            'html/canvas/MouseEventHitRegion.h',
             'html/canvas/OESElementIndexUint.cpp',
             'html/canvas/OESElementIndexUint.h',
             'html/canvas/OESStandardDerivatives.cpp',
             'html/canvas/OESStandardDerivatives.h',
             'html/canvas/OESTextureFloat.cpp',
             'html/canvas/OESTextureFloat.h',
             'html/canvas/OESTextureFloatLinear.cpp',
             'html/canvas/OESTextureFloatLinear.h',
             'html/canvas/OESTextureHalfFloat.cpp',
             'html/canvas/OESTextureHalfFloat.h',
@@ skipping 863 matching lines @@
             'loader/MixedContentCheckerTest.cpp',
             'page/NetworkStateNotifierTest.cpp',
             'rendering/RenderOverflowTest.cpp',
             'rendering/shapes/BoxShapeTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }