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

content/browser/gamepad/gamepad_service.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 CONTENT_BROWSER_GAMEPAD_GAMEPAD_SERVICE_H
 #define CONTENT_BROWSER_GAMEPAD_GAMEPAD_SERVICE_H
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 42 matching lines @@
   void Terminate();
 
  private:
   friend struct DefaultSingletonTraits<GamepadService>;
   friend class GamepadServiceTestConstructor;
 
   GamepadService();
 
   // Constructor for testing. This specifies the data fetcher to use for a
   // provider, bypassing the default platform one.
-  GamepadService(scoped_ptr<GamepadDataFetcher> fetcher);
+  explicit GamepadService(scoped_ptr<GamepadDataFetcher> fetcher);
 
   virtual ~GamepadService();
 
   int num_readers_;
   scoped_ptr<GamepadProvider> provider_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(GamepadService);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_SERVICE_H_