Add WebUSB layout tests for device disconnection.
These tests ensure that when a device has been disconnected and thus
the Mojo pipe between the renderer and browser process is closed calls
to methods on the USBDevice object fail correctly by rejecting with a
NotFoundError.
At the moment this requires WebUSBDeviceImpl to explicitly monitor for
connection errors and reset its interface pointer. Ideally this should
happen automatically.
BUG=492204
Review URL: https://codereview.chromium.org/1754543003
Cr-Commit-Position: refs/heads/master@{#378816}
4 files changed
