[StyleGuide] Allow let in JavaScript code

In https://codereview.chromium.org/2466263003 we realized that we should think
about our strategy for allowing `let` in Catapult. charliea@ proposed three
options for moving to allow it:

* Allow `let` but don't recommend it
* Recommend it for new code, but not for old code
* Recommend it for new code and require fixes to old code as it is modified.

On the basis that block scoping is a win for developer productivity, it makes
sense to recommend `let` in at least some cases, which throws out the first
option.

Given that requiring fixes to old code will almost certainly annoy
people, and the promise of --fix one day working with processors, that seems to
leave the second option as the best possible one.

BUG=catapult:#2833

Review-Url: https://codereview.chromium.org/2621643003
1 file changed
tree: 6545b6c80f96ab6d253b6a79b2f37b29f891986d
  1. bin/
  2. catapult_build/
  3. common/
  4. dashboard/
  5. dependency_manager/
  6. devil/
  7. docs/
  8. experimental/
  9. firefighter/
  10. hooks/
  11. infra/
  12. netlog_viewer/
  13. systrace/
  14. telemetry/
  15. third_party/
  16. trace_processor/
  17. tracing/
  18. .eslintignore
  19. .eslintrc
  20. .gitignore
  21. AUTHORS
  22. codereview.settings
  23. CONTRIBUTING.md
  24. LICENSE
  25. navbar.md
  26. OWNERS
  27. PRESUBMIT.py
  28. pylintrc
  29. README.md
  30. WATCHLISTS
README.md

Catapult

Catapult is the home for several performance tools that span from gathering, displaying and analyzing performance data. This includes:

These tools were created by Chromium developers for performance analysis, testing, and monitoring of Chrome, but they can also be used for analyzing and monitoring websites, and eventually Android apps.

Contributing

Please see our contributor's guide

Current build status