Explicitly put serial port fd in non-blocking mode on Chrome OS.

Explicitly put serial port fd in non-blocking mode on Chrome OS.

On Chrome OS the serial port is opened by the permission broker service,
which does not open the file descriptor in non-blocking mode. Chrome
should thus explicitly put the file descriptor in this mode to match the
flags set on other platforms.

Since r408467 we have relied on the file being in non-blocking mode to
test for data available as soon as it is open.

BUG=644017
Review-Url: https://codereview.chromium.org/2494513002
Cr-Commit-Position: refs/heads/master@{#431026}
(cherry picked from commit 0366454d38a76aba066b183f2f8132a15e26b385)

Committed: https://chromium.googlesource.com/chromium/src/+/7bc4382e2f3885ae85ea398de2e0d4013b0d2348

[Reilly Grant (use Gerrit), 2016-11-10 20:25:53]

Description was changed from

==========
Explicitly put serial port fd in non-blocking mode on Chrome OS.

On Chrome OS the serial port is opened by the permission broker service,
which does not open the file descriptor in non-blocking mode. Chrome
should thus explicitly put the file descriptor in this mode to match the
flags set on other platforms.

Since r408467 we have relied on the file being in non-blocking mode to
test for data available as soon as it is open.

BUG=644017

Review-Url: https://codereview.chromium.org/2494513002
Cr-Commit-Position: refs/heads/master@{#431026}
(cherry picked from commit 0366454d38a76aba066b183f2f8132a15e26b385)
==========

to

==========
Explicitly put serial port fd in non-blocking mode on Chrome OS.

On Chrome OS the serial port is opened by the permission broker service,
which does not open the file descriptor in non-blocking mode. Chrome
should thus explicitly put the file descriptor in this mode to match the
flags set on other platforms.

Since r408467 we have relied on the file being in non-blocking mode to
test for data available as soon as it is open.

BUG=644017

Review-Url: https://codereview.chromium.org/2494513002
Cr-Commit-Position: refs/heads/master@{#431026}
(cherry picked from commit 0366454d38a76aba066b183f2f8132a15e26b385)

Committed:
https://chromium.googlesource.com/chromium/src/+/7bc4382e2f3885ae85ea398de2e0...
==========

[Reilly Grant (use Gerrit), 2016-11-10 20:25:54]

Committed patchset #1 (id:1) manually as
7bc4382e2f3885ae85ea398de2e0d4013b0d2348.