Revert of Add tests for Chrome Stability Metrics.

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
Committed: https://crrev.com/c9e354be49d6abb003817f3e5a8a9f8ed17d09fa
Cr-Commit-Position: refs/heads/master@{#346567}

[Will Harris, 2015-09-01 04:16:52]

Created Revert of Add tests for Chrome Stability Metrics.

[commit-bot: I haz the power, 2015-09-01 04:17:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1321313002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1321313002/1

[commit-bot: I haz the power, 2015-09-01 04:17:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-01 04:18:16]

Patchset 1 (id:??) landed as
https://crrev.com/c9e354be49d6abb003817f3e5a8a9f8ed17d09fa
Cr-Commit-Position: refs/heads/master@{#346567}