Initial implementation of stashed message ports, layout tests

LayoutTests/http/tests/serviceworker/resources/stashed-ports-basics.js

+importScripts('worker-testharness.js');
+
+// Helper method that waits for a reply on a port, and resolves a promise with
+// the reply.
+function wait_for_message_to_port(test, port) {
+  return new Promise(function(resolve) {
+    var resolved = false;
+    port.onmessage = test.step_func(function(event) {
+      assert_false(resolved);
+      resolved = true;
+      resolve(event.data);
+    });
+  });
+}
+
+// Similar helper method, but waits for a reply to a stashed port with a
+// particular name.
+function wait_for_message_to_stashed_port(test, name) {
+  return new Promise(function(resolve) {
+    var event_handler = function(e) {
+      if (e.source.name === name) {
+        self.ports.removeEventListener('message', event_handler);
+        resolve(e);
+      }
+    };
+    self.ports.addEventListener('message', event_handler);
+  });
+}
+
+test(function(test) {
+    var channel = new MessageChannel();
+    var name = 'somename';
+    var stashed_port = self.ports.add(name, channel.port1);
+    assert_equals(stashed_port.name, name);
+  }, 'Name set when adding port is set correctly.');
+
+promise_test(function(test) {
+    var channel = new MessageChannel();
+    var stashed_port = self.ports.add('', channel.port1);
+    stashed_port.postMessage('pingy ping');
+    return wait_for_message_to_port(test, channel.port2)
+      .then(test.step_func(function(reply) {
+          assert_equals(reply, 'pingy ping');
+      }));
+  }, 'Messages posted into stashed port arrive on other side.');
+
+promise_test(function(test) {
+    var channel = new MessageChannel();
+    var name = 'test_events';
+    var stashed_port = self.ports.add(name, channel.port1);
+    channel.port2.postMessage('ping blah');
+    return wait_for_message_to_stashed_port(test, name)
+      .then(test.step_func(function(reply) {
+          assert_equals(reply.data, 'ping blah');
+          assert_equals(reply.source, stashed_port);
+      }));
+  }, 'Messages sent to stashed port arrive as global events.');