WebRTC is not shown in shields on Tor tab as blocked

[LaurenWags]

Description

WebRTC is being blocked in a Tor window/tab (per #1254) however, it is not being shown as blocked in shields as it was on b-l.

Steps to Reproduce

1. Open https://diafygi.github.io/webrtc-ips/ in Tor Window
2. Look at shields icon.

Actual result:

No badge with number of blocked items is displayed. Click on shields, verify all items are 0 regardless of whether shields are up or down:

Expected result:

Shields should show WebRTC blocked as they do on b-l for a Tor tab (regardless of whether shields are up or down):

Reproduces how often:

easy

Brave version (chrome://version info)

Brave	0.55.11 Chromium: 70.0.3538.35 (Official Build) beta(64-bit)
Revision	28dcb499844fa40c28d5f62e337876cb936f79f5-refs/branch-heads/3538@{#678}
OS	Mac OS X

Brave	0.56.2 Chromium: 70.0.3538.35 (Official Build) dev (64-bit)
Revision	28dcb499844fa40c28d5f62e337876cb936f79f5-refs/branch-heads/3538@{#678}
OS	Mac OS X

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds? yes, both
• Does it reproduce on browser-laptop? no, works as expected on b-l

Website problems only:

• Does the issue resolve itself when disabling Brave Shields? no
• Is the issue reproducible on the latest version of Chrome? n/a

Additional Information

If you visit https://diafygi.github.io/webrtc-ips/ in a normal tab and block all fingerprinting, shields correctly shows 1 Fingerprinting method blocked.

[tomlowenthal]

I think that the resolution here should be that the WebRTC blocks on Tor modes in particular should be exposed to shields so that we can put it in the UI.