The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642

commit d83aa53f1beb27037f5f77fc06d5b6b0c2e05642
Author: reillyg <reillyg@chromium.org>
Date: Tue Mar 22 19:54:05 2016

Close USB device connections when the page is hidden.

This is a temporary measure to make up for the lack of a visible
indication that a page has an open connection to a USB device. If the
page becomes hidden then all open device connections are closed and
cannot be reopened until it is visible again.

BUG= 595375 

Review URL: https://codereview.chromium.org/1820173002

Cr-Commit-Position: refs/heads/master@{#382654}

[add] https://crrev.com/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642/third_party/WebKit/LayoutTests/usb/disconnect-when-hidden-or-closed.html
[modify] https://crrev.com/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642/third_party/WebKit/LayoutTests/usb/resources/usb-helpers.js
[modify] https://crrev.com/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642/third_party/WebKit/LayoutTests/usb/usbDevice.html
[modify] https://crrev.com/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642/third_party/WebKit/Source/modules/webusb/USBDevice.cpp
[modify] https://crrev.com/d83aa53f1beb27037f5f77fc06d5b6b0c2e05642/third_party/WebKit/Source/modules/webusb/USBDevice.h

The patch above automatically disconnects pages from devices when the tab moves to the background (equivalent to the page calling USBDevice.close()) and prevents the page from re-opening the device until it is in the foreground again. estark@, please mark this "Fixed" if you believe this is sufficient.

Thanks!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4c3ab3d07108f906137537c771de9b5bda0ef83c

commit 4c3ab3d07108f906137537c771de9b5bda0ef83c
Author: reillyg <reillyg@chromium.org>
Date: Fri Apr 08 22:11:54 2016

Remove page visibility requirement for WebUSB.

Now that there is a tab indicator for WebUSB it can be used from a tab
that is not in the foreground.

BUG= 595375 , 592105 

Review URL: https://codereview.chromium.org/1857393002

Cr-Commit-Position: refs/heads/master@{#386221}

[delete] https://crrev.com/0992e8345174e4f16c6949a7982125ee82455b61/third_party/WebKit/LayoutTests/usb/disconnect-when-hidden-or-closed.html
[modify] https://crrev.com/4c3ab3d07108f906137537c771de9b5bda0ef83c/third_party/WebKit/Source/modules/webusb/USBDevice.cpp
[modify] https://crrev.com/4c3ab3d07108f906137537c771de9b5bda0ef83c/third_party/WebKit/Source/modules/webusb/USBDevice.h

Security>UX component is deprecated in favor of the Team-Security-UX label