Bug 1570212 - Convert dom.securecontext.whitelist_onions to a static pref. r=mccr8

Differential Revision: https://phabricator.services.mozilla.com/D40160

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

dom/security/nsMixedContentBlocker.cpp

@@ -36,6 +36,7 @@
 #include "prnetdb.h"
 
 #include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_dom.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/ipc/URIUtils.h"
@@ -387,14 +388,7 @@ bool nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackURL(nsIURI* aURL) {
  * `dom.securecontext.whitelist_onions` is `true`.
  */
 bool nsMixedContentBlocker::IsPotentiallyTrustworthyOnion(nsIURI* aURL) {
-  static bool sInited = false;
-  static bool sWhiteListOnions = false;
-  if (!sInited) {
-    Preferences::AddBoolVarCache(&sWhiteListOnions,
-                                 "dom.securecontext.whitelist_onions");
-    sInited = true;
-  }
-  if (!sWhiteListOnions) {
+  if (!StaticPrefs::dom_securecontext_whitelist_onions()) {
     return false;
   }
 

modules/libpref/init/StaticPrefList.yaml

@@ -1900,6 +1900,11 @@
   value: true
   mirror: always
 
+- name: dom.securecontext.whitelist_onions
+  type: bool
+  value: false
+  mirror: always
+
 # This pref enables FeaturePolicy logic and the parsing of 'allow' attribute in
 # HTMLIFrameElement objects.
 - name: dom.security.featurePolicy.enabled