Remove usage of /deep/

[ebidel]

Intent to deprecate has gone out. Eventually /deep/ will be aliased to "". This means our usage of /deep/ in gathers (document.querySelecotorAll('html /deep/ *')) will become document.querySelecotorAll('html *') and we'll miss out on nodes within shadow trees.

We'll need to switch over to DOM traversal.

email that went to blink-dev: https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/68qSZM5QMRQ/pT2YCqZSomAJ

[ebidel]

/deep/ is being removed in Chrome 60. I'll get going on this.

https://www.chromestatus.com/feature/4964279606312960

[ebidel]

Filed an upstream FR ^ (ChromeDevTools/devtools-protocol#19) to add better support for this int he DT protocol. We can get all nodes with the substrees fairly easily, but making DOM.querySelector[All] shadow dom aware would be more flexible, long-term.