GitLab

Specifically:
 -  Fixing several type violations and adding JS type checking for
    - test_site_settings_prefs_browser_proxy.js
    - test_local_data_browser_proxy.js
    - test_util.js
 - Removing usage of mockMethods() from
   TestSiteSettingsPrefsBrowserProxy, as this pattern is incompatible
   with static type checking.
 - Updating various js_library() targets with missing dependencies as
   needed.

Bug: 1000989
Change-Id: I6b6924804ac96b048c6bde98e0101a7e90b4472a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2183015
Commit-Queue: dpapad <dpapad@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#766541}