Remove bogus DCHECKs in enumeration processing.

Remove bogus DCHECKs in enumeration processing.

These DCHECKs are intended to ensure that only one reply per device-type
per request is received from the browser.
However, the browser can send multiple replies if a device is added or
removed before the request is completed.
This is no problem, as the latest reply is used in case of multiple replies.

The bug is difficult to simulate in an automated test because it involves
addition and removal of devices with precise timing, but it is very easy
to reproduce manually.

BUG=607179
Committed: https://crrev.com/039cd143ff3e7d6c58fc8a6e85029d4f19e58b7d
Cr-Commit-Position: refs/heads/master@{#390360}

[Guido Urdaneta, 2016-04-27 14:58:07]

guidou@chromium.org changed reviewers:
+ perkj@chromium.org

[Guido Urdaneta, 2016-04-27 14:58:08]

Hi, another tiny CL, but this one actually does something :)

[perkj_chrome, 2016-04-28 12:08:45]

lgtm

[Guido Urdaneta, 2016-04-28 12:11:21]

The CQ bit was checked by guidou@chromium.org

[commit-bot: I haz the power, 2016-04-28 12:11:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1926723002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1926723002/1

[commit-bot: I haz the power, 2016-04-28 13:02:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-30 17:17:54]

Patchset 1 (id:??) landed as
https://crrev.com/039cd143ff3e7d6c58fc8a6e85029d4f19e58b7d
Cr-Commit-Position: refs/heads/master@{#390360}

[commit-bot: I haz the power, 2016-04-30 17:55:25]

Description was changed from

==========
Remove bogus DCHECKs in enumeration processing.

These DCHECKs are intended to ensure that only one reply per device-type
per request is received from the browser.
However, the browser can send multiple replies if a device is added or
removed before the request is completed.
This is no problem, as the latest reply is used in case of multiple replies.

The bug is difficult to simulate in an automated test because it involves
addition and removal of devices with precise timing, but it is very easy
to reproduce manually.

BUG=607179
==========

to

==========
Remove bogus DCHECKs in enumeration processing.

These DCHECKs are intended to ensure that only one reply per device-type
per request is received from the browser.
However, the browser can send multiple replies if a device is added or
removed before the request is completed.
This is no problem, as the latest reply is used in case of multiple replies.

The bug is difficult to simulate in an automated test because it involves
addition and removal of devices with precise timing, but it is very easy
to reproduce manually.

BUG=607179

Committed: https://crrev.com/039cd143ff3e7d6c58fc8a6e85029d4f19e58b7d
Cr-Commit-Position: refs/heads/master@{#390360}
==========