[USB Internals Test] Add test for rendering device descriptors

Added UI test with same logic of user's journey.
- Added test for rendering a new tab after user inspecting a device.
- Added test for displaying the device descriptors correcty with correct
  response and short response. Make sure two views and error can
  displayed well, and the mapping effect works.
Also added fake UsbDeviceProxy class to implement the functions that
needed for test.

Bug: 928923
Change-Id: Ifb87ef48eb42eb515937607cda0a2d1c433f3941
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1616382
Commit-Queue: Nancy Li <nancyly@google.com>
Reviewed-by: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663360}
3 files changed