Bug 1169159 - Make xpcshells run_test_in_child() and do_await_remote_message() return promises. r=ted,gfritzsche

testing/xpcshell/head.js

@@ -1239,11 +1239,19 @@ function do_load_child_test_harness()
  * @param optionalCallback.
  *        Optional function to be called (in parent) when test on child is
  *        complete.  If provided, the function must call do_test_finished();
+ * @return Promise Resolved when the test in the child is complete.
  */
 function run_test_in_child(testFile, optionalCallback)
 {
-  var callback = (typeof optionalCallback == 'undefined') ? 
-                    do_test_finished : optionalCallback;
+  return new Promise((resolve) => {
+    var callback = () => {
+      resolve();
+      if (typeof optionalCallback == 'undefined') {
+        do_test_finished();
+      } else {
+        optionalCallback();
+      }
+    };
 
     do_load_child_test_harness();
 
@@ -1254,22 +1262,33 @@ function run_test_in_child(testFile, optionalCallback)
                 + "_execute_test(); "
                 + "_testLogger.info('CHILD-TEST-COMPLETED');",
                 callback);
+  });
 }
 
 /**
  * Execute a given function as soon as a particular cross-process message is received.
  * Must be paired with do_send_remote_message or equivalent ProcessMessageManager calls.
+ *
+ * @param optionalCallback
+ *        Optional callback that is invoked when the message is received.  If provided,
+ *        the function must call do_test_finished().
+ * @return Promise Promise that is resolved when the message is received.
  */
-function do_await_remote_message(name, callback)
+function do_await_remote_message(name, optionalCallback)
 {
+  return new Promise((resolve) => {
     var listener = {
       receiveMessage: function(message) {
         if (message.name == name) {
           mm.removeMessageListener(name, listener);
-        callback();
+          resolve();
+          if (optionalCallback) {
+            optionalCallback();
+          } else {
             do_test_finished();
           }
         }
+      }
     };
 
     var mm;
@@ -1280,6 +1299,7 @@ function do_await_remote_message(name, callback)
     }
     do_test_pending();
     mm.addMessageListener(name, listener);
+  });
 }
 
 /**