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Specifically:
 - Replace var with let/const (using lebab)
 - Fix missing/extra semicolon violations
 - Fix missing curly braces violations
 - Fix double quotes violations
 - Fix JS naming violations
 - clang-format
 - Add PRESUBMIT to catch these automatically moving forward.

Bug: 986001,792774
Change-Id: I1d180fd3557243e08b0009c4fdc122ffa742b505
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1716094
Auto-Submit: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680372}