This reverts commit 66c50ea1.

Reason for revert:
Breaks some OWNERS checks. See https://crbug.com/684270 for details.

Original change's description:
> Fix OWNERS canned check to avoid duplicate output.
>
> 1. Update PanProjectChecks() to supply source_filter to CheckOwners().
>    This prevents files under e.g. third_party/WebKit being checked both
>    by the top-level and sub-directory PRESUBMIT rules.
> 2. Fix CheckOwners() to list missing-OWNERS only for the sub-directory
>    it is invoked on, rather than the whole CL. This prevents files under
>    sub-directories with their own PRESUBMIT rule, within the same repo,
>    from causing OWNERS to be checked for files outside that directory.
>
> BUG=
>
> Reviewed-on: https://chromium-review.googlesource.com/426003

TBR=wez@chromium.org,dcheng@chromium.org
BUG=684270

Change-Id: I094818a6fa3e16fbac0d37d2596a40210611ee05
Reviewed-on: https://chromium-review.googlesource.com/431656Reviewed-by: Dirk Pranke <dpranke@chromium.org>