Implement OffscreenCanvas.getContext('webgl')

third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp

Index: third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
index d8fc5499e8353cd8b66d41b603d308331e675cc1..c29ee2edaff56468396cbafb960066cd73193a5d 100644
--- a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
@@ -19,7 +19,7 @@ OffscreenCanvasRenderingContext2D::~OffscreenCanvasRenderingContext2D()
 }
 
 OffscreenCanvasRenderingContext2D::OffscreenCanvasRenderingContext2D(OffscreenCanvas* canvas, const CanvasContextCreationAttributes& attrs)
-    : CanvasRenderingContext(canvas)
+    : CanvasRenderingContext(static_cast<HTMLCanvasElement*>(nullptr), canvas)
     , m_hasAlpha(attrs.alpha())
 {
 }
@@ -85,6 +85,11 @@ ImageBitmap* OffscreenCanvasRenderingContext2D::transferToImageBitmap(ExceptionS
     return ImageBitmap::create(image.release());
 }
 
+void OffscreenCanvasRenderingContext2D::setOffscreenCanvasGetContextResult(OffscreenRenderingContext& result)
+{
+    result.setOffscreenCanvasRenderingContext2D(this);
+}
+
 bool OffscreenCanvasRenderingContext2D::parseColorOrCurrentColor(Color& color, const String& colorString) const
 {
     return ::blink::parseColorOrCurrentColor(color, colorString, nullptr);