Add missing (and remove superfluous) 'explicit' from constructors.

net/base/network_config_watcher_mac.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 "net/base/network_config_watcher_mac.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 12 matching lines @@
                           CFArrayRef changed_keys,
                           void* config_delegate) {
   NetworkConfigWatcherMac::Delegate* net_config_delegate =
       static_cast<NetworkConfigWatcherMac::Delegate*>(config_delegate);
   net_config_delegate->OnNetworkConfigChange(changed_keys);
 }
 #endif  // !defined(OS_IOS)
 
 class NetworkConfigWatcherMacThread : public base::Thread {
  public:
-  NetworkConfigWatcherMacThread(NetworkConfigWatcherMac::Delegate* delegate);
+  explicit NetworkConfigWatcherMacThread(
+      NetworkConfigWatcherMac::Delegate* delegate);
   virtual ~NetworkConfigWatcherMacThread();
 
  protected:
   // base::Thread
   virtual void Init() OVERRIDE;
   virtual void CleanUp() OVERRIDE;
 
  private:
   // The SystemConfiguration calls in this function can lead to contention early
   // on, so we invoke this function later on in startup to keep it fast.
@@ skipping 79 matching lines @@
   // We create this notifier thread because the notification implementation
   // needs a thread with a CFRunLoop, and there's no guarantee that
   // MessageLoop::current() meets that criterion.
   base::Thread::Options thread_options(MessageLoop::TYPE_UI, 0);
   notifier_thread_->StartWithOptions(thread_options);
 }
 
 NetworkConfigWatcherMac::~NetworkConfigWatcherMac() {}
 
 }  // namespace net