Fix up HotwordServiceTest on Chrome-branded builds.

Fix up HotwordServiceTest on Chrome-branded builds.

The ENABLE_HOTWORDING flag is not available in
hotword_service_unittest.cc, so all tests were assuming hotwording was
disabled (since r333548). This has been failing on Official builders
since r335874.

Since it's hard to resolve this in a simple way (we want to merge these
changes), just disabling the tests is the cleanest option for now.

BUG=503963
Committed: https://crrev.com/8ef0bc35b1594ad013dc2ae1d6893e0091919271
Cr-Commit-Position: refs/heads/master@{#336091}

[Matt Giuca, 2015-06-25 03:09:12]

mgiuca@chromium.org changed reviewers:
+ kcarattini@chromium.org

[Nico, 2015-06-25 03:38:01]

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

[Nico, 2015-06-25 03:38:02]

lgtm

[Nico, 2015-06-25 03:38:16]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-06-25 03:38:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1207163002/20001

[kcarattini, 2015-06-25 04:15:44]

lgtm

[commit-bot: I haz the power, 2015-06-25 04:19:25]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-25 04:20:27]

Patchset 2 (id:??) landed as
https://crrev.com/8ef0bc35b1594ad013dc2ae1d6893e0091919271
Cr-Commit-Position: refs/heads/master@{#336091}