Bug 1622111 - Convert dom.use_components_shim to static pref. r=njn

Converts dom.use_components_shim to a static pref and removes its `all.js` entry.

Differential Revision: https://phabricator.services.mozilla.com/D67184

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

dom/base/nsGlobalWindowInner.cpp

@@ -2813,14 +2813,7 @@ bool nsGlobalWindowInner::DoResolve(
   // We support a cut-down Components.interfaces in case websites are
   // using Components.interfaces.nsIFoo.CONSTANT_NAME for the ones
   // that have constants.
-  static bool watchingComponentsPref = false;
-  static bool useComponentsShim = false;
-  if (!watchingComponentsPref) {
-    watchingComponentsPref = true;
-    Preferences::AddBoolVarCache(&useComponentsShim, "dom.use_components_shim",
-                                 true);
-  }
-  if (useComponentsShim &&
+  if (StaticPrefs::dom_use_components_shim() &&
       aId == XPCJSRuntime::Get()->GetStringID(XPCJSContext::IDX_COMPONENTS)) {
     return ResolveComponentsShim(aCx, aObj, aDesc);
   }

modules/libpref/init/StaticPrefList.yaml

@@ -2657,6 +2657,12 @@
   value: 5000
   mirror: always
 
+# Whether to shim a Components object on untrusted windows.
+- name: dom.use_components_shim
+  type: bool
+  value: @IS_NOT_NIGHTLY_BUILD@
+  mirror: always
+
 - name: dom.vibrator.enabled
   type: bool
   value: true

modules/libpref/init/all.js

@@ -1047,13 +1047,6 @@ pref("dom.select_popup_in_parent.enabled", false);
 
 pref("dom.cycle_collector.incremental", true);
 
-// Whether to shim a Components object on untrusted windows.
-#ifdef NIGHTLY_BUILD
-  pref("dom.use_components_shim", false);
-#else // NIGHTLY_BUILD
-  pref("dom.use_components_shim", true);
-#endif // NIGHTLY_BUILD
-
 // Disable popups from plugins by default
 //   0 = openAllowed
 //   1 = openControlled