Revert of Add tests for Chrome Stability Metrics. (patchset #2 id:20001 of https://codereview.chromium.org/1323703002/ )

Reason for revert:
can't use extensions::ExtensionTest in chrome unit_tests, only in extensions_unittests. need to rethink this test.

Original issue's description:
> Add tests for Chrome Stability Metrics.
>
> BUG=526198,467920
>
> Committed: https://crrev.com/32a86c2579e167dd1e181676056c202f5191852d
> Cr-Commit-Position: refs/heads/master@{#346436}

TBR=asvitkine@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=526198,467920,526903

Review URL: https://codereview.chromium.org/1321313002

Cr-Commit-Position: refs/heads/master@{#346567}
5 files changed