[whatwg] [canvas] inner shadows

[Tyler Larson]

Shadows can be applied to the outside of anything. This is a great feature that is otherwise rather difficult to recreate but why not enable users to be able to have inner shadows? Things like beveling, embossing and many other stylistic things that are used in today designs rely on inner shadows. 
http://www.whatwg.org/specs/web-apps/current-work/#shadows

It could just be a boolean value noting if rendering is done to the inside or the outside of what is currently drawn into the context.
In CSS we have inset box-shadows, which gives a similar effect. 
http://www.w3.org/TR/css3-background/#the-box-shadow

Can we add this to the canvas shadows please?

-Tyler Larson