Add rendering context and rendering 2D context to OffscreenCanvas

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 2949 matching lines @@
             'html/canvas/CanvasDrawListener.cpp',
             'html/canvas/CanvasDrawListener.h',
             'html/canvas/CanvasFontCache.cpp',
             'html/canvas/CanvasFontCache.h',
             'html/canvas/CanvasImageSource.h',
             'html/canvas/CanvasRenderingContext.cpp',
             'html/canvas/CanvasRenderingContext.h',
             'html/canvas/CanvasRenderingContextFactory.h',
             'html/canvas/OffscreenCanvas.cpp',
             'html/canvas/OffscreenCanvas.h',
+            'html/canvas/OffscreenCanvasRenderingContext.cpp',
+            'html/canvas/OffscreenCanvasRenderingContext.h',
+            'html/canvas/OffscreenCanvasRenderingContextFactory.h',
             'html/forms/BaseButtonInputType.cpp',
             'html/forms/BaseButtonInputType.h',
             'html/forms/BaseCheckableInputType.cpp',
             'html/forms/BaseCheckableInputType.h',
             'html/forms/BaseChooserOnlyDateAndTimeInputType.cpp',
             'html/forms/BaseChooserOnlyDateAndTimeInputType.h',
             'html/forms/BaseClickableWithKeyInputType.cpp',
             'html/forms/BaseClickableWithKeyInputType.h',
             'html/forms/BaseDateAndTimeInputType.cpp',
             'html/forms/BaseDateAndTimeInputType.h',
@@ skipping 1059 matching lines @@
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }