DNR: Move ruleset matcher unittests to the extensions layer.

RulesetMatcher is a class in the extensions layer but it is unit-tested at the
chrome layer. Fix this by moving the tests to the extensions layer by removing
dependencies to chrome's extension loading code. This also means we don't
check the extension loading in these tests, but that is taken care of in the
browser tests.

BUG=930961

Change-Id: Ic971bce981a65cda8928a8e3d9e3b49f960b4aef
Reviewed-on: https://chromium-review.googlesource.com/c/1496314
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636663}
6 files changed