1 files changed, 38 insertions, 0 deletions
diff --git a/devtools/client/responsive.html/utils/message.js b/devtools/client/responsive.html/utils/message.js
new file mode 100644
index 000000000..d5c5b012f
--- /dev/null
+++ b/devtools/client/responsive.html/utils/message.js
@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const promise = require("promise");
+
+const REQUEST_DONE_SUFFIX = ":done";
+
+function wait(win, type) {
+  let deferred = promise.defer();
+
+  let onMessage = event => {
+    if (event.data.type !== type) {
+      return;
+    }
+    win.removeEventListener("message", onMessage);
+    deferred.resolve();
+  };
+  win.addEventListener("message", onMessage);
+
+  return deferred.promise;
+}
+
+function post(win, type) {
+  win.postMessage({ type }, "*");
+}
+
+function request(win, type) {
+  let done = wait(win, type + REQUEST_DONE_SUFFIX);
+  post(win, type);
+  return done;
+}
+
+exports.wait = wait;
+exports.post = post;
+exports.request = request;