re-support selectors like `:host[inline]` since this was previously supported under shady-dom.
re-support selectors like `:host[inline]` since this was previously supported under shady-dom.

MartinsThiago/polymer,mgiuffrida/polymer,gronke/polymer,Polymer/polymer,mgiuffrida/polymer,ktiedt/polymer,JeremybellEU/polymer,ktiedt/polymer,MartinsThiago/polymer,jordanyaker/polymer,jordanyaker/polymer,JeremybellEU/polymer,ikeagold/polymer,ktiedt/polymer,gronke/polymer,gronke/polymer,jordanyaker/polymer,ikeagold/polymer,MartinsThiago/polymer,yforrest/polymer,Polymer/polymer,Polymer/polymer,yforrest/polymer,JeremybellEU/polymer,ikeagold/polymer,mgiuffrida/polymer,yforrest/polymer