WebBluetooth - Scanning should use the same device id hashing as Gatt.

This CL adds a new method to WebBluetoothDeviceId which allows us to
create a device id from a device address without adding any services
which allows scanning to share the same device address -> device id
origin specific mapping.

Bug: 897312
Change-Id: Ib3dda1c2d47138486c1457eb25a8dc602b52e2f0
Reviewed-on: https://chromium-review.googlesource.com/c/1405368
Commit-Queue: Doug Turner <dougt@chromium.org>
Reviewed-by: Ovidio de Jesús Ruiz-Henríquez <odejesush@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623520}
7 files changed