Enable ExtensionApiTest.MessagingUserGesture test.

chrome/browser/extensions/extension_messages_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/base64.h"
 #include "base/files/file_path.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/path_service.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 973 matching lines @@
       chromium_connectable.get(), true, close_background_message());
   EXPECT_EQ(expected_tls_channel_id_value, tls_channel_id);
   // A subsequent connect will still succeed, even if the background page was
   // previously closed.
   tls_channel_id =
       GetTlsChannelIdFromPortConnect(chromium_connectable.get(), true);
    // And the expected value is still retrieved.
   EXPECT_EQ(expected_tls_channel_id_value, tls_channel_id);
 }
 
-// FIXME: Enable after https://codereview.chromium.org/518633002/ lands
-IN_PROC_BROWSER_TEST_F(ExtensionApiTest, DISABLED_MessagingUserGesture) {
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, MessagingUserGesture) {
   const char kManifest[] = "{"
                           "  \"name\": \"user_gesture\","
                           "  \"version\": \"1.0\","
                           "  \"background\": {"
                           "    \"scripts\": [\"background.js\"]"
                           "  },"
                           "  \"manifest_version\": 2"
                           "}";
 
   TestExtensionDir receiver_dir;
@@ skipping 76 matching lines @@
   ui_test_utils::NavigateToURL(browser(), chromium_org_url());
   EXPECT_EQ(COULD_NOT_ESTABLISH_CONNECTION_ERROR,
             CanConnectAndSendMessagesToMainFrame(invalid.get()));
 }
 
 #endif  // !defined(OS_WIN) - http://crbug.com/350517.
 
 }  // namespace
 
 };  // namespace extensions