Bug 1484843 - Add policy for disabling DNS over HTTPS r=flod,Felipe,jkt

Differential Revision: https://phabricator.services.mozilla.com/D7743

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

browser/components/enterprisepolicies/Policies.jsm

@@ -198,6 +198,26 @@ var Policies = {
     },
   },
 
+  "DNSOverHTTPS": {
+    onBeforeAddons(manager, param) {
+      if ("Enabled" in param) {
+        let mode = param.Enabled ? 2 : 5;
+        if (param.Locked) {
+          setAndLockPref("network.trr.mode", mode);
+        } else {
+          setDefaultPref("network.trr.mode", mode);
+        }
+      }
+      if (param.ProviderURL) {
+        if (param.Locked) {
+          setAndLockPref("network.trr.uri", param.ProviderURL.href);
+        } else {
+          setDefaultPref("network.trr.uri", param.ProviderURL.href);
+        }
+      }
+    },
+  },
+
   "DisableAppUpdate": {
     onBeforeAddons(manager, param) {
       if (param) {

browser/components/enterprisepolicies/schemas/policies-schema.json

@@ -141,6 +141,21 @@
       }
     },
 
+    "DNSOverHTTPS": {
+      "type": "object",
+      "properties": {
+        "Enabled": {
+          "type": "boolean"
+        },
+        "ProviderURL": {
+          "type": "URLorEmpty"
+        },
+        "Locked": {
+          "type": "boolean"
+        }
+      }
+    },
+
     "DisableAppUpdate": {
       "machine_only": true,
 

browser/components/enterprisepolicies/tests/browser/browser_policies_simple_pref_policies.js

@@ -154,6 +154,35 @@ const POLICIES_TESTS = [
       "privacy.clearOnShutdown.offlineApps": true,
     },
   },
+
+  // POLICY: DNSOverHTTPS Locked
+  {
+    policies: {
+      "DNSOverHTTPS": {
+        "Enabled": true,
+        "ProviderURL": "http://example.com/provider",
+        "Locked": true,
+      },
+    },
+    lockedPrefs: {
+      "network.trr.mode": 2,
+      "network.trr.uri": "http://example.com/provider",
+    },
+  },
+
+  // POLICY: DNSOverHTTPS Unlocked
+  {
+    policies: {
+      "DNSOverHTTPS": {
+        "Enabled": false,
+        "ProviderURL": "http://example.com/provider",
+      },
+    },
+    unlockedPrefs: {
+      "network.trr.mode": 5,
+      "network.trr.uri": "http://example.com/provider",
+    },
+  },
 ];
 
 add_task(async function test_policy_remember_passwords() {

browser/locales/en-US/browser/policies/policies-descriptions.ftl

@@ -70,6 +70,8 @@ policy-DisplayBookmarksToolbar = Display the Bookmarks Toolbar by default.
 
 policy-DisplayMenuBar = Display the Menu Bar by default.
 
+policy-DNSOverHTTPS = Configure DNS over HTTPS.
+
 policy-DontCheckDefaultBrowser = Disable check for default browser on startup.
 
 # “lock” means that the user won’t be able to change this setting