Add UNKNOWN_CELLULAR network type and allow unknown network type in NetworkMonitor

This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the network type, it helps bind sockets to the network.

BUG=
R=glaznev@webrtc.org

Committed: https://crrev.com/e59122889fc6e480238613558c67de13747ae487
Cr-Commit-Position: refs/heads/master@{#13351}

[honghaiz3, 2016-06-30 18:25:52]

Description was changed from

==========
Allow unknown network type in AndroidNetworkMonitor.
This fixes an issue that some Android devices returns an unknown network
type but that is filtered out by AndroidNetworkMonitor.

BUG=
==========

to

==========
This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the
network type, it helps bind sockets to the network. 

BUG=
==========

[honghaiz3, 2016-06-30 18:26:51]

Patchset #1 (id:1) has been deleted

[honghaiz3, 2016-06-30 18:29:20]

honghaiz@webrtc.org changed reviewers:
+ glaznev@webrtc.org

[honghaiz3, 2016-06-30 18:30:29]

The CQ bit was checked by honghaiz@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2016-06-30 18:30:36]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-06-30 18:44:02]

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

[commit-bot: I haz the power, 2016-06-30 18:44:03]

Dry run: Try jobs failed on following builders:
  android_dbg on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/android_dbg/builds/14706)

[AlexG, 2016-06-30 18:52:13]

lgtm

[honghaiz3, 2016-06-30 20:00:08]

Description was changed from

==========
This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the
network type, it helps bind sockets to the network. 

BUG=
==========

to

==========
This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the
network type, it helps bind sockets to the network.

BUG=
R=glaznev@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/e59122889fc6e480238613558...
==========

[honghaiz3, 2016-06-30 20:00:10]

Committed patchset #1 (id:20001) manually as
e59122889fc6e480238613558c67de13747ae487 (presubmit successful).

[commit-bot: I haz the power, 2016-06-30 20:00:12]

Description was changed from

==========
This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the
network type, it helps bind sockets to the network.

BUG=
R=glaznev@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/e59122889fc6e480238613558...
==========

to

==========
This helps recognize more network types
and even if the "unknown" network type is not helpful for identifying the
network type, it helps bind sockets to the network.

BUG=
R=glaznev@webrtc.org

Committed: https://crrev.com/e59122889fc6e480238613558c67de13747ae487
Cr-Commit-Position: refs/heads/master@{#13351}
==========