Update from chromium https://crrev.com/301725/

net/dns/serial_worker_unittest.cc

 // Copyright (c) 2011 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 "net/dns/serial_worker.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 78 matching lines @@
 
   // Lets OnWork run and waits for it to complete. Can only return if OnWork is
   // executed on a concurrent thread.
   void WaitForWork() {
     RunUntilBreak("OnWork");
     work_allowed_.Signal();
     work_called_.Wait();
   }
 
   // test::Test methods
-  virtual void SetUp() override {
+  void SetUp() override {
     message_loop_ = base::MessageLoop::current();
     worker_ = new TestSerialWorker(this);
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     // Cancel the worker to catch if it makes a late DoWork call.
     worker_->Cancel();
     // Check if OnWork is stalled.
     EXPECT_FALSE(work_running_) << "OnWork should be done by TearDown";
     // Release it for cleanliness.
     if (work_running_) {
       WaitForWork();
     }
   }
 
@@ skipping 39 matching lines @@
   RunUntilBreak("OnWorkFinished");
 
   // No more tasks should remain.
   EXPECT_TRUE(message_loop_->IsIdleForTesting());
 }
 
 }  // namespace
 
 }  // namespace net