Make clients bindings associated for WebUsbService.

Bug: 699790
Change-Id: I7fd6e119db118da8a00810e1015a4464d1a00cc4
Reviewed-on: https://chromium-review.googlesource.com/1224971
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Donna Wu <donna.wu@intel.com>
Cr-Commit-Position: refs/heads/master@{#592682}
8 files changed