Detect duplicate USB device notifications from udev.

Detect duplicate USB device notifications from udev.

This patch adds a check to detect when udev has sent Chrome multiple
notifications for the same device, ignoring the duplicates, as this
behavior has been observed in the wild.

I also fix DeviceReady() to not send a device added notification if a
device was disconnected while it was being enumerated. The device would
not have been added to the global device list in this case.

BUG=638298
Review-Url: https://codereview.chromium.org/2261783002
Cr-Commit-Position: refs/heads/master@{#413273}
(cherry picked from commit f2c7b56f4a4f2c16b2f7062f60ad3041217e9f20)

Committed: https://chromium.googlesource.com/chromium/src/+/b69683e7f0dc6fcb3d06db36d4ada51fe56c3c18

[Reilly Grant (use Gerrit), 2016-08-23 17:34:44]

Description was changed from

==========
Detect duplicate USB device notifications from udev.

This patch adds a check to detect when udev has sent Chrome multiple
notifications for the same device, ignoring the duplicates, as this
behavior has been observed in the wild.

I also fix DeviceReady() to not send a device added notification if a
device was disconnected while it was being enumerated. The device would
not have been added to the global device list in this case.

BUG=638298

Review-Url: https://codereview.chromium.org/2261783002
Cr-Commit-Position: refs/heads/master@{#413273}
(cherry picked from commit f2c7b56f4a4f2c16b2f7062f60ad3041217e9f20)
==========

to

==========
Detect duplicate USB device notifications from udev.

This patch adds a check to detect when udev has sent Chrome multiple
notifications for the same device, ignoring the duplicates, as this
behavior has been observed in the wild.

I also fix DeviceReady() to not send a device added notification if a
device was disconnected while it was being enumerated. The device would
not have been added to the global device list in this case.

BUG=638298

Review-Url: https://codereview.chromium.org/2261783002
Cr-Commit-Position: refs/heads/master@{#413273}
(cherry picked from commit f2c7b56f4a4f2c16b2f7062f60ad3041217e9f20)

Committed:
https://chromium.googlesource.com/chromium/src/+/b69683e7f0dc6fcb3d06db36d4ad...
==========

[Reilly Grant (use Gerrit), 2016-08-23 17:34:46]

Committed patchset #1 (id:1) manually as
b69683e7f0dc6fcb3d06db36d4ada51fe56c3c18.