cannot copy/save canvas images

How to reproduce:

• Open one of the browser examples.
• Load a web page with a canvas element, e.g. http://www.w3schools.com/html/html5_canvas.asp
• Right click the canvas.

Expected result:

• A context menu with a "Copy Image" entry (in dev even "Save Image")

Looks like the CopyImageToClipboard web action is never added to the standard context menu, because contextMenuData.mediaUrl is not valid for canvases.