Add /chrome/test/media_router/internal to .gitignore

Add /chrome/test/media_router/internal to .gitignore

BUG=503787
Committed: https://crrev.com/33aa1cab237ca76a9edd0ef74583c173bf4aa77e
Cr-Commit-Position: refs/heads/master@{#339145}

[smut, 2015-06-24 22:49:12]

smut@google.com changed reviewers:
+ iannucci@chromium.org, leilei@google.com

[Lei Lei, 2015-06-24 22:51:26]

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

[Lei Lei, 2015-06-24 22:51:26]

lgtm

[smut, 2015-06-24 22:57:40]

The CQ bit was checked by smut@google.com

[commit-bot: I haz the power, 2015-06-24 22:59:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1201343005/1

[commit-bot: I haz the power, 2015-06-24 22:59:49]

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

[commit-bot: I haz the power, 2015-06-24 22:59:50]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Lei Lei, 2015-07-15 18:12:16]

Friendly ping. Robbie, could you take a look?

[iannucci, 2015-07-16 22:10:14]

The CQ bit was checked by iannucci@chromium.org

[iannucci, 2015-07-16 22:10:15]

lgtm

[commit-bot: I haz the power, 2015-07-16 22:10:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1201343005/1

[commit-bot: I haz the power, 2015-07-16 22:53:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-16 22:55:22]

Patchset 1 (id:??) landed as
https://crrev.com/33aa1cab237ca76a9edd0ef74583c173bf4aa77e
Cr-Commit-Position: refs/heads/master@{#339145}