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* Use temps for some minor repeated expressions, whose calculation will
  get slightly more cumbersome later.
* Other minor code movement to reduce later diffs.

Bug: none
Change-Id: I87d466901608191d9be3ecd0cbeea256e68e2937
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2021462
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737911}