Move cast_channel API tests to extensions_unittests suite

Move cast_channel API tests to extensions_unittests suite

They don't need to run in Chrome's unit_tests

BUG=397164
TEST=extensions_unittests

Committed: https://crrev.com/0f9a432e5e5fe32767111f1ff4db558839852d1b
Cr-Commit-Position: refs/heads/master@{#293643}

[James Cook, 2014-09-05 17:36:08]

jamescook@chromium.org changed reviewers:
+ yoz@chromium.org

[James Cook, 2014-09-05 17:36:09]

yoz, PTAL

wez, just FYI about the cleanup

[Yoyo Zhou, 2014-09-05 18:39:40]

LGTM

[James Cook, 2014-09-05 19:41:31]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2014-09-05 19:42:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jamescook@chromium.org/545293002/1

[Wez, 2014-09-05 21:44:54]

wez@chromium.org changed reviewers:
+ wez@chromium.org

[Wez, 2014-09-05 21:44:55]

+kmarshall, mfoltz: FYI

[commit-bot: I haz the power, 2014-09-06 01:44:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-09-06 01:44:43]

Exceeded time limit waiting for builds to trigger.

[James Cook, 2014-09-07 00:06:12]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2014-09-07 00:06:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jamescook@chromium.org/545293002/1

[commit-bot: I haz the power, 2014-09-07 00:07:48]

Committed patchset #1 (id:1) as 9344b54ad4df6961a818e1dc5c6a7692ea946ed1

[commit-bot: I haz the power, 2014-09-10 03:43:37]

Patchset 1 (id:??) landed as
https://crrev.com/0f9a432e5e5fe32767111f1ff4db558839852d1b
Cr-Commit-Position: refs/heads/master@{#293643}