Not documented.
Source
@DomName('CanvasRenderingContext2D.getContextAttributes')
@DocsEditable()
// http://wiki.whatwg.org/wiki/CanvasOpaque#Suggested_IDL
@Experimental()
Canvas2DContextAttributes getContextAttributes() => _blink.BlinkCanvasRenderingContext2D.instance.getContextAttributes_Callback_0_(this);