Use dictionaries for context creation attributes. Eliminate custom bindings.

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/AnimationNode.idl',
@@ skipping 207 matching lines @@
             'html/MediaKeyError.idl',
             'html/MediaKeyEvent.idl',
             'html/RadioNodeList.idl',
             'html/TextMetrics.idl',
             'html/TimeRanges.idl',
             'html/ValidityState.idl',
             'html/VoidCallback.idl',
             'html/canvas/ANGLEInstancedArrays.idl',
             'html/canvas/CHROMIUMSubscribeUniform.idl',
             'html/canvas/CHROMIUMValuebuffer.idl',
-            'html/canvas/Canvas2DContextAttributes.idl',
             'html/canvas/CanvasGradient.idl',
             'html/canvas/CanvasPattern.idl',
             'html/canvas/CanvasRenderingContext2D.idl',
             'html/canvas/EXTBlendMinMax.idl',
             'html/canvas/EXTFragDepth.idl',
             'html/canvas/EXTShaderTextureLOD.idl',
             'html/canvas/EXTTextureFilterAnisotropic.idl',
             'html/canvas/EXTsRGB.idl',
             'html/canvas/OESElementIndexUint.idl',
             'html/canvas/OESStandardDerivatives.idl',
             'html/canvas/OESTextureFloat.idl',
             'html/canvas/OESTextureFloatLinear.idl',
             'html/canvas/OESTextureHalfFloat.idl',
             'html/canvas/OESTextureHalfFloatLinear.idl',
             'html/canvas/OESVertexArrayObject.idl',
             'html/canvas/Path2D.idl',
             'html/canvas/WebGLActiveInfo.idl',
             'html/canvas/WebGLBuffer.idl',
             'html/canvas/WebGLCompressedTextureATC.idl',
             'html/canvas/WebGLCompressedTextureETC1.idl',
             'html/canvas/WebGLCompressedTexturePVRTC.idl',
             'html/canvas/WebGLCompressedTextureS3TC.idl',
-            'html/canvas/WebGLContextAttributes.idl',
             'html/canvas/WebGLContextEvent.idl',
             'html/canvas/WebGLDebugRendererInfo.idl',
             'html/canvas/WebGLDebugShaders.idl',
             'html/canvas/WebGLDepthTexture.idl',
             'html/canvas/WebGLDrawBuffers.idl',
             'html/canvas/WebGLFramebuffer.idl',
             'html/canvas/WebGLLoseContext.idl',
             'html/canvas/WebGLProgram.idl',
             'html/canvas/WebGLRenderbuffer.idl',
             'html/canvas/WebGLRenderingContext.idl',
@@ skipping 2356 matching lines @@
             'html/ValidityState.cpp',
             'html/ValidityState.h',
             'html/WindowNameCollection.cpp',
             'html/WindowNameCollection.h',
             'html/canvas/ANGLEInstancedArrays.cpp',
             'html/canvas/ANGLEInstancedArrays.h',
             'html/canvas/CHROMIUMSubscribeUniform.cpp',
             'html/canvas/CHROMIUMSubscribeUniform.h',
             'html/canvas/CHROMIUMValuebuffer.cpp',
             'html/canvas/CHROMIUMValuebuffer.h',
-            'html/canvas/Canvas2DContextAttributes.cpp',
-            'html/canvas/Canvas2DContextAttributes.h',
-            'html/canvas/CanvasContextAttributes.cpp',
-            'html/canvas/CanvasContextAttributes.h',
             'html/canvas/CanvasGradient.cpp',
             'html/canvas/CanvasGradient.h',
             'html/canvas/CanvasImageSource.h',
             'html/canvas/CanvasPathMethods.cpp',
             'html/canvas/CanvasPathMethods.h',
             'html/canvas/CanvasPattern.cpp',
             'html/canvas/CanvasPattern.h',
             'html/canvas/CanvasRenderingContext.cpp',
             'html/canvas/CanvasRenderingContext.h',
             'html/canvas/CanvasRenderingContext2D.cpp',
             'html/canvas/CanvasRenderingContext2D.h',
             'html/canvas/CanvasStyle.cpp',
             'html/canvas/CanvasStyle.h',
+            'html/canvas/ContextAttributeHelpers.cpp',
+            'html/canvas/ContextAttributeHelpers.h',
             'html/canvas/ClipList.cpp',
             'html/canvas/ClipList.h',
             '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',
@@ skipping 23 matching lines @@
             'html/canvas/WebGLBuffer.cpp',
             'html/canvas/WebGLBuffer.h',
             'html/canvas/WebGLCompressedTextureATC.cpp',
             'html/canvas/WebGLCompressedTextureATC.h',
             'html/canvas/WebGLCompressedTextureETC1.cpp',
             'html/canvas/WebGLCompressedTextureETC1.h',
             'html/canvas/WebGLCompressedTexturePVRTC.cpp',
             'html/canvas/WebGLCompressedTexturePVRTC.h',
             'html/canvas/WebGLCompressedTextureS3TC.cpp',
             'html/canvas/WebGLCompressedTextureS3TC.h',
-            'html/canvas/WebGLContextAttributes.cpp',
-            'html/canvas/WebGLContextAttributes.h',
             'html/canvas/WebGLContextEvent.cpp',
             'html/canvas/WebGLContextEvent.h',
             'html/canvas/WebGLContextGroup.cpp',
             'html/canvas/WebGLContextGroup.h',
             'html/canvas/WebGLContextObject.cpp',
             'html/canvas/WebGLContextObject.h',
             'html/canvas/WebGLDebugRendererInfo.cpp',
             'html/canvas/WebGLDebugRendererInfo.h',
             'html/canvas/WebGLDebugShaders.cpp',
             'html/canvas/WebGLDebugShaders.h',
@@ skipping 698 matching lines @@
             'svg/properties/SVGPropertyTearOff.cpp',
         ],
         'core_dictionary_idl_files': [
             'css/FontFaceDescriptors.idl',
             'dom/DOMPointInit.idl',
             'dom/ElementRegistrationOptions.idl',
             'dom/MutationObserverInit.idl',
             'events/EventInit.idl',
             'frame/ScrollOptions.idl',
             'frame/ScrollToOptions.idl',
+            'html/canvas/Canvas2DContextAttributes.idl',
+            'html/canvas/CanvasContextCreationAttributes.idl',
             'html/canvas/HitRegionOptions.idl',
+            'html/canvas/WebGLContextAttributes.idl',
             'html/track/TrackEventInit.idl',
             'page/EventSourceInit.idl',
             'storage/StorageEventInit.idl',
         ],
         'generated_core_dictionary_files': [
             '<(blink_core_output_dir)/css/FontFaceDescriptors.cpp',
             '<(blink_core_output_dir)/css/FontFaceDescriptors.h',
             '<(blink_core_output_dir)/dom/DOMPointInit.cpp',
             '<(blink_core_output_dir)/dom/DOMPointInit.h',
             '<(blink_core_output_dir)/dom/ElementRegistrationOptions.cpp',
             '<(blink_core_output_dir)/dom/ElementRegistrationOptions.h',
             '<(blink_core_output_dir)/dom/MutationObserverInit.cpp',
             '<(blink_core_output_dir)/dom/MutationObserverInit.h',
             '<(blink_core_output_dir)/events/EventInitDictionary.cpp',
             '<(blink_core_output_dir)/events/EventInitDictionary.h',
             '<(blink_core_output_dir)/frame/ScrollOptions.cpp',
             '<(blink_core_output_dir)/frame/ScrollOptions.h',
             '<(blink_core_output_dir)/frame/ScrollToOptions.cpp',
             '<(blink_core_output_dir)/frame/ScrollToOptions.h',
+            '<(blink_core_output_dir)/html/canvas/Canvas2DContextAttributes.cpp',
+            '<(blink_core_output_dir)/html/canvas/Canvas2DContextAttributes.h',
+            '<(blink_core_output_dir)/html/canvas/CanvasContextCreationAttributes.cpp',
+            '<(blink_core_output_dir)/html/canvas/CanvasContextCreationAttributes.h',
             '<(blink_core_output_dir)/html/canvas/HitRegionOptions.cpp',
             '<(blink_core_output_dir)/html/canvas/HitRegionOptions.h',
+            '<(blink_core_output_dir)/html/canvas/WebGLContextAttributes.cpp',
+            '<(blink_core_output_dir)/html/canvas/WebGLContextAttributes.h',
             '<(blink_core_output_dir)/html/track/TrackEventInit.cpp',
             '<(blink_core_output_dir)/html/track/TrackEventInit.h',
             '<(blink_core_output_dir)/page/EventSourceInit.cpp',
             '<(blink_core_output_dir)/page/EventSourceInit.h',
             '<(blink_core_output_dir)/storage/StorageEventInit.cpp',
             '<(blink_core_output_dir)/storage/StorageEventInit.h',
         ],
         'core_testing_dictionary_idl_files': [
             'testing/InternalDictionary.idl',
             'testing/InternalDictionaryDerived.idl',
@@ skipping 174 matching lines @@
             'rendering/style/OutlineValueTest.cpp',
             'rendering/style/RenderStyleTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }