[merge to m60] Treat tethered networks as mobile networks

[merge to m60] Treat tethered networks as mobile networks

merge to m60 on behalf of weidongg@

This is additional CL to support update over cellular.
- add a property in NetworkState indicating tethering state.
- show a warning message in about Chrome OS page on tethered networks.

TBR=xiyuan@chromium.org, stevenjb@chromium.org
BUG=691108
Review-Url: https://codereview.chromium.org/2919683002
Cr-Original-Commit-Position: refs/heads/master@{#476464}
Review-Url: https://codereview.chromium.org/2933323004 .
Cr-Commit-Position: refs/branch-heads/3112@{#334}
Cr-Branched-From: b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed: https://chromium.googlesource.com/chromium/src/+/caaa7bc498dc0e8d8e06732452cf57e863372464

[Qiang(Joe) Xu, 2017-06-14 01:27:22]

Description was changed from

==========
[merge to m60] Treat tethered networks as mobile networks

merge to m60 on behalf of weidongg@

This is additional CL to support update over cellular.
- add a property in NetworkState indicating tethering state.
- show a warning message in about Chrome OS page on tethered networks.

TBR=xiyuan@chromium.org, stevenjb@chromium.org
BUG=691108

Review-Url: https://codereview.chromium.org/2919683002
Cr-Commit-Position: refs/heads/master@{#476464}
(cherry picked from commit 4432cf04a40645d3c8f2d972e0181ec7a1c6a093)
==========

to

==========
[merge to m60] Treat tethered networks as mobile networks

merge to m60 on behalf of weidongg@

This is additional CL to support update over cellular.
- add a property in NetworkState indicating tethering state.
- show a warning message in about Chrome OS page on tethered networks.

TBR=xiyuan@chromium.org, stevenjb@chromium.org
BUG=691108

Review-Url: https://codereview.chromium.org/2919683002
Cr-Original-Commit-Position: refs/heads/master@{#476464}
Review-Url: https://codereview.chromium.org/2933323004 .
Cr-Commit-Position: refs/branch-heads/3112@{#334}
Cr-Branched-From:
b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed:
https://chromium.googlesource.com/chromium/src/+/caaa7bc498dc0e8d8e06732452cf...
==========

[Qiang(Joe) Xu, 2017-06-14 01:27:23]

Committed patchset #1 (id:1) manually as
caaa7bc498dc0e8d8e06732452cf57e863372464 (presubmit successful).