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- Try to make the tasks more general purpose.
  * Add mechanism to switch output directories. Most
    tasks will work with this value.
  * Add tasks to run tests for the current file or directory
    instead of pre-determined targets.
- Try to simplify it.
  * Remove some parameters which are defaults
  * Move pattern matches to top-level, to avoid duplicates.

Change-Id: Ifff15bc264be510c0859e4adcce7b996349ac343
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2402189Reviewed-by: Chase Phillips <cmp@chromium.org>
Commit-Queue: Chase Phillips <cmp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805872}