Deprecation Warning: Styling master document from stylesheets defined in HTML Imports is deprecated

[WillsB3]

Hey,

We're using this component in production, and started noticing that it appears to be using web platform features which are soon to be deprecated, at which point I assume the player may break...

From the console on the demo page:

[Deprecation] Styling master document from stylesheets defined in HTML Imports is deprecated, and is planned to be removed in M65, around March 2018. Please refer to https://goo.gl/EGXzpw for possible migration paths.

I've never done any Polymer development so I don't know if this is an easy fix. I'll do a bit more investigating to see if I might be able to raise a small PR to fix it but I worry that it might require fundamental changes to the component...

Thanks

[WillsB3]

Hummm I think this is partially being caused by some of the dependencies of this component too - It looks like some of the core Polymer components also trigger this error. Polymer issue 4679 appears to track the fix for this.

I've also come across Polymer Issue 5017 which looks like it might be what we need to use to silence the deprecation warning raised by this components <style> tags, but again I've not done much with Polymer so I'm not really sure if that is the case.