Delay WebUSB initialization until after browser startup.

Delay WebUSB initialization until after browser startup.

Initializing the WebUSB device detector module causes the USB service to
be initialized and enumerate all USB device connected to the system.
This can cause unnecessary delay during browser startup. The purpose of
this module is to detect devices connected after Chrome starts to
display a notification so it doesn't matter if it is initialized after
first page load.

An UMA histogram for the time spent initializing the detector is also
added to aid further investigation of this issue.

BUG=642107
Committed: https://crrev.com/478a62181383d2cc7fa545ee6a7a91ab34fec477
Cr-Commit-Position: refs/heads/master@{#415971}

[Reilly Grant (use Gerrit), 2016-08-31 00:45:29]

Description was changed from

==========
Delay WebUSB initialization until after browser startup.

Initializing the WebUSB device detector module causes the USB service to
be initialized and enumerate all USB device connected to the system.
This can cause unnecessary delay during browser startup. The purpose of
this module is to detect devices connected after Chrome starts to
display a notification so it doesn't matter if it is initialized after
first page load.

BUG=642107
==========

to

==========
Delay WebUSB initialization until after browser startup.

Initializing the WebUSB device detector module causes the USB service to
be initialized and enumerate all USB device connected to the system.
This can cause unnecessary delay during browser startup. The purpose of
this module is to detect devices connected after Chrome starts to
display a notification so it doesn't matter if it is initialized after
first page load.

An UMA histogram for the time spent initializing the detector is also
added to aid further investigation of this issue.

BUG=642107
==========

[Reilly Grant (use Gerrit), 2016-08-31 00:45:29]

reillyg@chromium.org changed reviewers:
+ jochen@chromium.org

[Reilly Grant (use Gerrit), 2016-08-31 00:45:49]

Please take a look.

[jochen (gone - plz use gerrit), 2016-08-31 14:33:33]

the code changes look good, however, you'll need a separate reviewer for the
histogram - I can only approve changes to blink use counter histograms

[Reilly Grant (use Gerrit), 2016-08-31 17:09:06]

reillyg@chromium.org changed reviewers:
+ holte@chromium.org

[Reilly Grant (use Gerrit), 2016-08-31 17:09:07]

holte@ please review histograms.xml.

[Reilly Grant (use Gerrit), 2016-08-31 17:10:02]

On 2016/08/31 at 14:33:33, jochen wrote:
> the code changes look good, however, you'll need a separate reviewer for the
histogram - I can only approve changes to blink use counter histograms

Ah, that explains why an additional histograms owner wasn't originally
suggested.

[Steven Holte, 2016-08-31 21:52:38]

histograms lgtm

[jochen (gone - plz use gerrit), 2016-09-01 12:14:34]

lgtm

[Reilly Grant (use Gerrit), 2016-09-01 15:38:21]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2016-09-01 15:38:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-01 16:43:39]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-09-01 16:45:43]

Description was changed from

==========
Delay WebUSB initialization until after browser startup.

Initializing the WebUSB device detector module causes the USB service to
be initialized and enumerate all USB device connected to the system.
This can cause unnecessary delay during browser startup. The purpose of
this module is to detect devices connected after Chrome starts to
display a notification so it doesn't matter if it is initialized after
first page load.

An UMA histogram for the time spent initializing the detector is also
added to aid further investigation of this issue.

BUG=642107
==========

to

==========
Delay WebUSB initialization until after browser startup.

Initializing the WebUSB device detector module causes the USB service to
be initialized and enumerate all USB device connected to the system.
This can cause unnecessary delay during browser startup. The purpose of
this module is to detect devices connected after Chrome starts to
display a notification so it doesn't matter if it is initialized after
first page load.

An UMA histogram for the time spent initializing the detector is also
added to aid further investigation of this issue.

BUG=642107

Committed: https://crrev.com/478a62181383d2cc7fa545ee6a7a91ab34fec477
Cr-Commit-Position: refs/heads/master@{#415971}
==========

[commit-bot: I haz the power, 2016-09-01 16:45:44]

Patchset 2 (id:??) landed as
https://crrev.com/478a62181383d2cc7fa545ee6a7a91ab34fec477
Cr-Commit-Position: refs/heads/master@{#415971}