Use dictionaries for context creation attributes. Eliminate custom bindings.

Source/core/core.gypi

Index: Source/core/core.gypi
diff --git a/Source/core/core.gypi b/Source/core/core.gypi
index 2c9c58612da4b443bf89f6b2262b3a525758eea1..077a64d06be928329438af97ea6696435c2c7708 100644
--- a/Source/core/core.gypi
+++ b/Source/core/core.gypi
@@ -225,7 +225,6 @@
             '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',
@@ -248,7 +247,6 @@
             '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',
@@ -2632,10 +2630,6 @@
             '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',
@@ -2649,6 +2643,8 @@
             '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',
@@ -2692,8 +2688,6 @@
             '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',
@@ -3414,7 +3408,10 @@
             'frame/ScrollOptions.idl',
             'frame/ScrollToOptions.idl',
             'html/MediaKeyEventInit.idl',
+            'html/canvas/Canvas2DContextAttributes.idl',
+            'html/canvas/CanvasContextCreationAttributes.idl',
             'html/canvas/HitRegionOptions.idl',
+            'html/canvas/WebGLContextAttributes.idl',
             'html/canvas/WebGLContextEventInit.idl',
             'html/track/TrackEventInit.idl',
             'page/EventSourceInit.idl',
@@ -3439,8 +3436,14 @@
             '<(blink_core_output_dir)/frame/ScrollToOptions.h',
             '<(blink_core_output_dir)/html/MediaKeyEventInit.cpp',
             '<(blink_core_output_dir)/html/MediaKeyEventInit.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/canvas/WebGLContextEventInit.cpp',
             '<(blink_core_output_dir)/html/canvas/WebGLContextEventInit.h',
             '<(blink_core_output_dir)/html/track/TrackEventInit.cpp',