Special case bitmap renderers in Document::getCSSCanvasContext

https://bugs.webkit.org/show_bug.cgi?id=241505

Patch by Rob Buis <rbuis@igalia.com> on 2022-06-10
Reviewed by Alex Christensen.

Special case bitmap renderers in Document::getCSSCanvasContext.

* Source/WebCore/dom/Document.cpp:
(WebCore::Document::getCSSCanvasContext):

Canonical link: https://commits.webkit.org/251463@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295457 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/dom/Document.cpp

@@ -6580,6 +6580,9 @@ std::optional<RenderingContext> Document::getCSSCanvasContext(const String& type
         return RenderingContext { RefPtr<WebGL2RenderingContext> { &downcast<WebGL2RenderingContext>(*context) } };
 #endif
 
+    if (is<ImageBitmapRenderingContext>(*context))
+        return RenderingContext { RefPtr<ImageBitmapRenderingContext> { &downcast<ImageBitmapRenderingContext>(*context) } };
+
     return RenderingContext { RefPtr<CanvasRenderingContext2D> { &downcast<CanvasRenderingContext2D>(*context) } };
 }