Replace invalid UTF-16 escape sequences
when decoding invalid UTF strings in chromedriver.

Web platform tests use ECMAScript strings which
aren't necessarily utf-16 characters.
This change will help us deal with that case.

More info: 
https://bugs.chromium.org/p/chromium/issues/detail?id=723592

To reproduce the error message from above, run:

./wptrun chrome url/url-constructor.html

on web platform tests.

Bug: 723592
Change-Id: Icf4b7de968ace81abba9f3020b9c123ab0791318
Reviewed-on: https://chromium-review.googlesource.com/565461
Commit-Queue: Jonathon Kereliuk <kereliuk@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487152}
4 files changed