import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

toolkit/content/tests/browser/head.js

@@ -0,0 +1,33 @@
+"use strict";
+
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Promise",
+  "resource://gre/modules/Promise.jsm");
+
+/**
+ * A wrapper for the findbar's method "close", which is not synchronous
+ * because of animation.
+ */
+function closeFindbarAndWait(findbar) {
+  return new Promise((resolve) => {
+    if (findbar.hidden) {
+      resolve();
+      return;
+    }
+    findbar.addEventListener("transitionend", function cont(aEvent) {
+      if (aEvent.propertyName != "visibility") {
+        return;
+      }
+      findbar.removeEventListener("transitionend", cont);
+      resolve();
+    });
+    findbar.close();
+  });
+}
+
+function pushPrefs(...aPrefs) {
+  let deferred = Promise.defer();
+  SpecialPowers.pushPrefEnv({"set": aPrefs}, deferred.resolve);
+  return deferred.promise;
+}