Bug 1565738 - Re-enable disabled WebRTC tests on macOS Mojave r=jib

Re-enable skipped webRTC tests on Mac which were disabled due to the macOS 10.14 permission prompts causing timeouts.

Don't trigger OS camera and microphone permission prompts for fake devices (used for tests).

Differential Revision: https://phabricator.services.mozilla.com/D46893

--HG--
extra : moz-landing-system : lando

browser/base/content/test/webrtc/browser.ini

@@ -5,25 +5,21 @@ support-files =
   get_user_media_in_xorigin_frame.html
   get_user_media_content_script.js
   head.js
-skip-if = os == 'mac' # most tests permafail on macosx1014, see individual bugs
+
 [browser_devices_get_user_media.js]
-skip-if = fission || (os == "linux" && debug) || os == 'mac' # linux: bug 976544, macosx1014 intermittent due to 1259330
+skip-if = fission || (os == "linux" && debug) # linux: bug 976544
 [browser_devices_get_user_media_anim.js]
-skip-if = os == 'mac' # macosx1014 permafail, see 1565738
 [browser_devices_get_user_media_default_permissions.js]
-skip-if = os == 'mac' # macosx1014 fails due to 1567656
 [browser_devices_get_user_media_in_frame.js]
-skip-if = debug || os == 'mac' # bug 1369731, macosx1014 due to 1567746
+skip-if = debug # bug 1369731
 [browser_devices_get_user_media_in_xorigin_frame.js]
-skip-if = debug || os == 'mac' # bug 1369731, macosx1014 due to 1567746
+skip-if = debug # bug 1369731
 [browser_devices_get_user_media_multi_process.js]
-skip-if =
-  (debug && os == "win") || os == "mac" || # bug 1393761, macosx1014 due to 1568142
-  fission # Fails intermittently.
+skip-if = (debug && os == "win") || fission # bug 1393761, fission fails intermittently
 [browser_devices_get_user_media_paused.js]
-skip-if = (os == "win" && !debug) || (os =="linux" && !debug && bits == 64) || os == 'mac' # macosx1014 due to 1567735, Bug 1440900
+skip-if = (os == "win" && !debug) || (os =="linux" && !debug && bits == 64) # Bug 1440900
 [browser_devices_get_user_media_screen.js]
-skip-if = (os == 'linux') || os == 'mac' # Bug 1503991, macosx1014 due to 1568135
+skip-if = (os == 'linux') # Bug 1503991
 [browser_devices_get_user_media_tear_off_tab.js]
 skip-if = fission
 [browser_devices_get_user_media_unprompted_access.js]
@@ -33,4 +29,3 @@ skip-if = fission || (os == "win" && bits == 64) # win8: bug 1334752
 [browser_devices_get_user_media_unprompted_access_queue_request.js]
 [browser_webrtc_hooks.js]
 [browser_devices_get_user_media_queue_request.js]
-skip-if = os == 'mac' # macosx1014 due to 1568141

browser/modules/webrtcUI.jsm

@@ -377,6 +377,13 @@ function denyRequestNoPermission(aBrowser, aRequest) {
 // the permission state has not yet been determined.
 //
 async function checkOSPermission(camNeeded, micNeeded) {
+  // Don't trigger OS permission requests for fake devices. Fake devices don't
+  // require OS permission and the dialogs are problematic in automated testing
+  // (where fake devices are used) because they require user interaction.
+  if (Services.prefs.getBoolPref("media.navigator.streams.fake", false)) {
+    return true;
+  }
+
   let camStatus = {},
     micStatus = {};
   OSPermissions.getMediaCapturePermissionState(camStatus, micStatus);