This is what the latest spec says.
All these now are prefixed with WebGL rather than Canvas.
It was impractical to do this renaming separately from the CanvasRenderingContext3D -> WebGLRenderingContext renaming in https://bugs.webkit.org/show_bug.cgi?id=29095 . Closing this as a duplicate and expanding the scope of the other bug. *** This bug has been marked as a duplicate of bug 29095 ***