Implement OffscreenCanvas.getContext('webgl')

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h"
 
 #include "bindings/modules/v8/UnionTypesModules.h"
 #include "core/frame/ImageBitmap.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "wtf/Assertions.h"
 
 #define UNIMPLEMENTED ASSERT_NOT_REACHED
 
 namespace blink {
 
 OffscreenCanvasRenderingContext2D::~OffscreenCanvasRenderingContext2D()
 {
 }
 
 OffscreenCanvasRenderingContext2D::OffscreenCanvasRenderingContext2D(OffscreenCanvas* canvas, const CanvasContextCreationAttributes& attrs)
-    : CanvasRenderingContext(canvas)
+    : CanvasRenderingContext(static_cast<HTMLCanvasElement*>(nullptr), canvas)

[haraken, 2016/04/28 11:14:50]

Is the static_cast needed?

     , m_hasAlpha(attrs.alpha())
 {
 }
 
 DEFINE_TRACE(OffscreenCanvasRenderingContext2D)
 {
     CanvasRenderingContext::trace(visitor);
     BaseRenderingContext2D::trace(visitor);
 }
 
@@ skipping 55 matching lines @@
 {
     if (!imageBuffer())
         return nullptr;
     // TODO: crbug.com/593514 Add support for GPU rendering
     RefPtr<SkImage> skImage = m_imageBuffer->newSkImageSnapshot(PreferNoAcceleration, SnapshotReasonUnknown);
     RefPtr<StaticBitmapImage> image = StaticBitmapImage::create(skImage.release());
     m_imageBuffer.clear(); // "Transfer" means no retained buffer
     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);
 }
 
 SkCanvas* OffscreenCanvasRenderingContext2D::drawingCanvas() const
 {
     ImageBuffer* buffer = imageBuffer();
     if (!buffer)
         return nullptr;
@@ skipping 43 matching lines @@
     }
 #endif
 }
 
 bool OffscreenCanvasRenderingContext2D::isContextLost() const
 {
     return false;
 }
 
 }