Bug 1543696 - Don't set extensions.legacy.enabled on beta in browser_ext_themes_experiment.js. r=kmag

Differential Revision: https://phabricator.services.mozilla.com/D27153

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

toolkit/components/extensions/test/browser/browser_ext_themes_experiment.js

@@ -3,9 +3,11 @@
 // This test checks whether the theme experiments work
 
 add_task(async function setup() {
-  await SpecialPowers.pushPrefEnv({
-    set: [["extensions.legacy.enabled", true]],
-  });
+  if (AppConstants.MOZ_ALLOW_LEGACY_EXTENSIONS) {
+    await SpecialPowers.pushPrefEnv({
+      set: [["extensions.legacy.enabled", true]],
+    });
+  }
 });
 
 add_task(async function test_experiment_static_theme() {

toolkit/components/extensions/test/browser/browser_ext_themes_warnings.js

@@ -73,7 +73,11 @@ add_task(async function test_dynamic_theme() {
 });
 
 add_task(async function test_experiment() {
-  Services.prefs.setBoolPref("extensions.legacy.enabled", true);
+  if (AppConstants.MOZ_ALLOW_LEGACY_EXTENSIONS) {
+    await SpecialPowers.pushPrefEnv({
+      set: [["extensions.legacy.enabled", true]],
+    });
+  }
 
   info("Testing that experiments are handled correctly when legacy pref is enabled");
 
@@ -107,7 +111,9 @@ add_task(async function test_experiment() {
 
   info("Testing that experiments are handled correctly when legacy pref is disabled");
 
-  Services.prefs.setBoolPref("extensions.legacy.enabled", false);
+  if (AppConstants.MOZ_ALLOW_LEGACY_EXTENSIONS) {
+    await SpecialPowers.popPrefEnv();
+  }
 
   extension = ExtensionTestUtils.loadExtension({
     manifest: {