[Chromecast] Reland "Ignore interfaces not used to connect to internet."

[Chromecast] Reland "Ignore interfaces not used to connect to internet."

Add NetworkChangeNotifierFactoryCast to create instance of
NetworkChangeNotifierLinux that ignores interfaces that will not be
used to connect to internet.

BUG=469863
R=gunsch@chromium.org

Committed: https://crrev.com/072a522258abaa50bfe7abdeb1b4bf66ad931c67
Cr-Commit-Position: refs/heads/master@{#329445}

[gunsch, 2015-05-12 17:53:30]

lgtm

[derekjchow1, 2015-05-12 18:09:34]

The CQ bit was checked by derekjchow@chromium.org

[commit-bot: I haz the power, 2015-05-12 18:10:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1138923002/1

[commit-bot: I haz the power, 2015-05-12 18:15:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-12 18:16:39]

Patchset 1 (id:??) landed as
https://crrev.com/072a522258abaa50bfe7abdeb1b4bf66ad931c67
Cr-Commit-Position: refs/heads/master@{#329445}