GitLab

* Use range-based for loops
* Use auto (sparingly) to replace ugly iterator naming
* Trust return value optimization to handle vectors

Change-Id: I14ef9fd8d9904b943b0e2d64188d3be5f63ef23d
Reviewed-on: https://chromium-review.googlesource.com/930163
Commit-Queue: Joshua Bell <jsbell@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543865}