Remove CanvasRenderingContext from the web exposed objects

Source/core/core.gypi

 {
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/Animation.idl',
             'animation/Player.idl',
             'animation/TimedItem.idl',
             'animation/Timeline.idl',
             'animation/Timing.idl',
             'clipboard/Clipboard.idl',
@@ skipping 200 matching lines @@
             'html/MediaKeyEvent.idl',
             'html/RadioNodeList.idl',
             'html/TextMetrics.idl',
             'html/TimeRanges.idl',
             'html/ValidityState.idl',
             'html/VoidCallback.idl',
             'html/canvas/ANGLEInstancedArrays.idl',
             'html/canvas/Canvas2DContextAttributes.idl',
             'html/canvas/CanvasGradient.idl',
             'html/canvas/CanvasPattern.idl',
-            'html/canvas/CanvasRenderingContext.idl',
             'html/canvas/CanvasRenderingContext2D.idl',
             'html/canvas/EXTFragDepth.idl',
             'html/canvas/EXTTextureFilterAnisotropic.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',
@@ skipping 3055 matching lines @@
             'html/parser/HTMLParserThreadTest.cpp',
             'html/track/vtt/BufferedLineReaderTest.cpp',
             'html/track/vtt/VTTScannerTest.cpp',
             'rendering/RenderOverflowTest.cpp',
             'rendering/shapes/BoxShapeTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
         ],
     }
 }