GitLab

Fix the implementation of get local storage keys and get session storage
keys functions.

Bug: chromedriver:2177
Change-Id: Iac8e8155081190d92dc14a54f9c367337f2ebe86
Reviewed-on: https://chromium-review.googlesource.com/844354Reviewed-by: Jonathon Kereliuk <kereliuk@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526485}