Fix initial USB enumeration on Linux to return all devices.

Fix initial USB enumeration on Linux to return all devices.

This patch fixes an issue where the first enumeration of USB devices on
Linux would only return a single device and observers would not be
notified of additional devices. This was because the logic to determine
if enumeration callbacks should be called was checking only that all
previously seen devices (of which there was only one at that point) were
ready and not that the sysfs tree had been completely walked.

BUG=662486
Review-Url: https://codereview.chromium.org/2523403002
Cr-Commit-Position: refs/heads/master@{#434718}
(cherry picked from commit 5c30282c70ec5f7f92129589fbbc84fef5738454)

Committed: https://chromium.googlesource.com/chromium/src/+/d26a894642fb6aca8c30b25753372d6814fbcb4e

[Reilly Grant (use Gerrit), 2016-11-29 20:30:34]

Description was changed from

==========
Fix initial USB enumeration on Linux to return all devices.

This patch fixes an issue where the first enumeration of USB devices on
Linux would only return a single device and observers would not be
notified of additional devices. This was because the logic to determine
if enumeration callbacks should be called was checking only that all
previously seen devices (of which there was only one at that point) were
ready and not that the sysfs tree had been completely walked.

BUG=662486

Review-Url: https://codereview.chromium.org/2523403002
Cr-Commit-Position: refs/heads/master@{#434718}
(cherry picked from commit 5c30282c70ec5f7f92129589fbbc84fef5738454)
==========

to

==========
Fix initial USB enumeration on Linux to return all devices.

This patch fixes an issue where the first enumeration of USB devices on
Linux would only return a single device and observers would not be
notified of additional devices. This was because the logic to determine
if enumeration callbacks should be called was checking only that all
previously seen devices (of which there was only one at that point) were
ready and not that the sysfs tree had been completely walked.

BUG=662486

Review-Url: https://codereview.chromium.org/2523403002
Cr-Commit-Position: refs/heads/master@{#434718}
(cherry picked from commit 5c30282c70ec5f7f92129589fbbc84fef5738454)

Committed:
https://chromium.googlesource.com/chromium/src/+/d26a894642fb6aca8c30b2575337...
==========

[Reilly Grant (use Gerrit), 2016-11-29 20:30:36]

Committed patchset #1 (id:1) manually as
d26a894642fb6aca8c30b25753372d6814fbcb4e.