[sensors][permission] Implement generic sensor permission checks

This CL implements a sensor provider proxy and changes
RenderFrameHostImpl to use that for forwarding sensor provider interface 
requests from renderers to the device service so that the proxy can
intercept the requests and allow or deny them based on permission
statuses.

This is the second part of adding permission guard for sensors based on
Generic Sensor Framework.

Bug: 606766
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_site_isolation
Change-Id: I39cf632600533acffe8f7f02e69fe11b9b7ca870
Reviewed-on: https://chromium-review.googlesource.com/552130
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Eero Häkkinen <eero.hakkinen@intel.com>
Cr-Commit-Position: refs/heads/master@{#495880}
7 files changed