Add node field to PolymerDomApi

[rictic]

And keep DomApiNative type compatible with PolymerDomApi.

Upstreaming cl/275091781

[aomarks]

I think this should go to legacy-undefined-noBatch, since that's what Google tracks?

[kevinpschaaf]

Either place... we're regularly merging master into legacy-undefined-noBatch.

[kevinpschaaf]

Curious what was relying on node? It's basically an implementation detail of the PolymerDomAPI class (despite it not being prefixed), so it smells odd that something would reference it.

[rictic]

It looks like it's from a desire to unwrap a PolymerDomApi value back to its underlying dom value in order to pass it to a basic DOM handling API. Might have been totally based on a type error from the compiler and it may have worked fine at runtime, in which case maybe they should just cast the PolymerDomApi as a Node instead.

To check out the code, see http://cs/setPolymerNodeContent

[kevinpschaaf]

@sorvell Can you review?

[sorvell]

I think this is basically fine. The original intent was that this was private, but it was never marked so and it's not going to change at this point so it seems ok.