Move extensions manifest tests to run in extensions_unittests

Move extensions manifest tests to run in extensions_unittests

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

* Move FileHandlersManifestTest
* Move ExternallyConnectableManifestTest
* Migrate some _manifest_features.json entries that should have been under
  src/extensions a while ago.

BUG=397165
TEST=extensions_unittests, unit_tests

Committed: https://crrev.com/a02b3e5b8ea70a6f362ef804ee552255b40a2c74
Cr-Commit-Position: refs/heads/master@{#295479}

[James Cook, 2014-09-17 18:14:23]

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

[James Cook, 2014-09-17 18:14:24]

yoz, PTAL

I'm working on another CL that removes the last tests. It's dependent on this
one for the _manifest_features.json changes.

[James Cook, 2014-09-17 21:46:03]

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

[James Cook, 2014-09-17 21:46:04]

To rockot, since yoz is OOO today

[Ken Rockot(use gerrit already), 2014-09-17 22:12:08]

lgtm

https://codereview.chromium.org/565423003/diff/1/chrome/common/extensions/api...
File chrome/common/extensions/api/_manifest_features.json (left):

https://codereview.chromium.org/565423003/diff/1/chrome/common/extensions/api...
chrome/common/extensions/api/_manifest_features.json:273: "name": {
Hah, this and version are particularly egregious omissions. I guess we aren't
validating manifest features in app_shell? o_o

[James Cook, 2014-09-17 22:18:31]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2014-09-17 22:20:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/565423003/20001

[commit-bot: I haz the power, 2014-09-18 00:21:24]

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

[commit-bot: I haz the power, 2014-09-18 00:21:26]

Exceeded time limit waiting for builds to trigger.

[James Cook, 2014-09-18 15:20:15]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2014-09-18 15:21:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/565423003/20001

[commit-bot: I haz the power, 2014-09-18 16:23:09]

Committed patchset #2 (id:20001) as dfc6f77fbef115c8fd381da1be8fa442dfdddbdc

[commit-bot: I haz the power, 2014-09-18 16:23:51]

Patchset 2 (id:??) landed as
https://crrev.com/a02b3e5b8ea70a6f362ef804ee552255b40a2c74
Cr-Commit-Position: refs/heads/master@{#295479}