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

remoting/client/client_context.h

 // 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.
 
 #ifndef REMOTING_CLIENT_CLIENT_CONTEXT_H_
 #define REMOTING_CLIENT_CLIENT_CONTEXT_H_
 
 #include <string>
 
 #include "base/threading/thread.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace remoting {
 
 // A class that manages threads and running context for the chromoting client
 // process.
 class ClientContext {
  public:
   // |main_task_runner| is the task runner for the main plugin thread
   // that is used for all PPAPI calls, e.g. network and graphics.
-  ClientContext(base::SingleThreadTaskRunner* main_task_runner);
+  explicit ClientContext(base::SingleThreadTaskRunner* main_task_runner);
   virtual ~ClientContext();
 
   void Start();
   void Stop();
 
   base::SingleThreadTaskRunner* main_task_runner();
   base::SingleThreadTaskRunner* decode_task_runner();
   base::SingleThreadTaskRunner* audio_decode_task_runner();
 
  private:
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
   // A thread that handles all video decode operations.
   base::Thread decode_thread_;
 
   // A thread that handles all audio decode operations.
   base::Thread audio_decode_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientContext);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_CLIENT_CONTEXT_H_