Fix flaky tests by disabling DeviceDiscoveryNotification service.

chrome/browser/ui/webui/local_discovery/local_discovery_ui_browsertest.cc

 // Copyright 2013 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 <stdint.h>
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 429 matching lines @@
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
 #if defined(OS_CHROMEOS)
     // On chromeos, don't sign in with the stub-user automatically.  Use the
     // kLoginUser instead.
     command_line->AppendSwitchASCII(chromeos::switches::kLoginUser,
                                     kSampleUser);
     command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile,
                                     chrome::kTestUserProfileDir);
 #endif
+    command_line->AppendSwitch(switches::kDisableDeviceDiscoveryNotifications);
     WebUIBrowserTest::SetUpCommandLine(command_line);
   }
 
   void RunFor(base::TimeDelta time_period) {
     base::CancelableCallback<void()> callback(
         base::Bind(&base::MessageLoop::QuitWhenIdle,
                    base::Unretained(base::MessageLoop::current())));
     base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
         FROM_HERE, callback.callback(), time_period);
 
@@ skipping 49 matching lines @@
 
   test_service_discovery_client()->SimulateReceive(
       kGoodbyePacket, sizeof(kGoodbyePacket));
 
   RunFor(base::TimeDelta::FromMilliseconds(1100));
 
   EXPECT_TRUE(WebUIBrowserTest::RunJavascriptTest("checkNoDevices"));
 }
 
 // Flaky: http://crbug.com/660669.
-IN_PROC_BROWSER_TEST_F(LocalDiscoveryUITest, DISABLED_RegisterTest) {
+IN_PROC_BROWSER_TEST_F(LocalDiscoveryUITest, RegisterTest) {
   TestMessageLoopCondition condition_token_claimed;
 
   ui_test_utils::NavigateToURL(browser(), GURL(
       chrome::kChromeUIDevicesURL));
   condition_devices_listed().Wait();
 
   test_service_discovery_client()->SimulateReceive(
       kAnnouncePacket, sizeof(kAnnouncePacket));
 
   base::RunLoop().RunUntilIdle();
@@ skipping 50 matching lines @@
       kAnnouncePacketRegistered, sizeof(kAnnouncePacketRegistered));
 
   base::RunLoop().RunUntilIdle();
 
   EXPECT_TRUE(WebUIBrowserTest::RunJavascriptTest("expectRegisterDone"));
 }
 
 }  // namespace
 
 }  // namespace local_discovery