Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks

Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks (patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks (patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
> https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linux%20Trusty%20Leak/builds/3557
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed: https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4f12aa93057cd
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed: https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f120e3fc9f10d3

TBR=yzshen@chromium.org,ortuno@chromium.org
BUG=705734
Review-Url: https://codereview.chromium.org/2788463005
Cr-Commit-Position: refs/heads/master@{#462203}
Committed: https://chromium.googlesource.com/chromium/src/+/08513f9d231c07202bb6b2956f045f128950c194

[Reilly Grant (use Gerrit), 2017-03-31 20:53:42]

Created Reland of actor WebUSB LayoutTests to separate out the Mojo service
mocks

[Reilly Grant (use Gerrit), 2017-03-31 20:54:05]

Description was changed from

==========
Reland of actor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=705734
==========

to

==========
Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=705734
==========

[Reilly Grant (use Gerrit), 2017-03-31 20:55:11]

Register onunload handler to clear interface overrides

[Reilly Grant (use Gerrit), 2017-03-31 20:55:15]

The CQ bit was checked by reillyg@chromium.org to run a CQ dry run

[Reilly Grant (use Gerrit), 2017-03-31 20:55:55]

The CQ bit was unchecked by reillyg@chromium.org

[Reilly Grant (use Gerrit), 2017-03-31 20:56:00]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2017-03-31 20:56:04]

Dry run: 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, 2017-03-31 20:56:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-31 20:56:15]

Dry run: This issue passed the CQ dry run.

[Reilly Grant (use Gerrit), 2017-04-05 19:26:30]

Description was changed from

==========
Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=705734
==========

to

==========
Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
BUG=705734
==========

[Reilly Grant (use Gerrit), 2017-04-05 19:26:34]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2017-04-05 19:27:05]

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, 2017-04-05 20:36:15]

CQ is committing da patch.

Bot data: {"patchset_id": 240001, "attempt_start_ts": 1491420394862080,
"parent_rev": "722584c2e23d7f2c75bc05d0bfb36f866ca71b4f", "commit_rev":
"08513f9d231c07202bb6b2956f045f128950c194"}

[commit-bot: I haz the power, 2017-04-05 20:37:06]

Description was changed from

==========
Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
BUG=705734
==========

to

==========
Reland of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2791573002/ )

Reason for revert:
Fixed the leak.

Original issue's description:
> Revert of Refactor WebUSB LayoutTests to separate out the Mojo service mocks
(patchset #1 id:1 of https://codereview.chromium.org/2775323003/ )
> 
> Reason for revert:
> Breaks leak bot:
> 
>
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
> 
> * usb/test-polyfil.html
> * usb/usb-connection-event.html
> * usb/usb.html
> * usb/usbDevice-iframe.html
> * usb/usbDevice.html
> 
> seem to be leaking :(
> 
> Original issue's description:
> > Refactor WebUSB LayoutTests to separate out the Mojo service mocks
> > 
> > In preparation for being able to upstream the existing WebUSB tests to
> > the Web Platform Tests repository this patch splits out the Mojo
> > service mocks into webusb-test.js. This file is a polyfil for a
> > fictional "WebUSB Test API" that could in theory be implemented by any
> > browser (an idea borrowed from a proposed plan for Web Bluetooth).
> > 
> > BUG=705734
> > 
> > Review-Url: https://codereview.chromium.org/2775323003
> > Cr-Commit-Position: refs/heads/master@{#460978}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/e1edfbbb4b3a192e210c031628e4...
> 
> TBR=yzshen@chromium.org,reillyg@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=705734
> 
> Review-Url: https://codereview.chromium.org/2791573002
> Cr-Commit-Position: refs/heads/master@{#461045}
> Committed:
https://chromium.googlesource.com/chromium/src/+/245d44d8347cb000d4d78b46b9f1...

TBR=yzshen@chromium.org,ortuno@chromium.org
BUG=705734

Review-Url: https://codereview.chromium.org/2788463005
Cr-Commit-Position: refs/heads/master@{#462203}
Committed:
https://chromium.googlesource.com/chromium/src/+/08513f9d231c07202bb6b2956f04...
==========

[commit-bot: I haz the power, 2017-04-05 20:37:07]

Committed patchset #2 (id:240001) as
https://chromium.googlesource.com/chromium/src/+/08513f9d231c07202bb6b2956f04...