Remove explicit keyword from multi-argument constructors

chrome/browser/ui/cocoa/download/download_shelf_mac.h

 // Copyright (c) 2010 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 CHROME_BROWSER_UI_COCOA_DOWNLOAD_DOWNLOAD_SHELF_MAC_H_
 #define CHROME_BROWSER_UI_COCOA_DOWNLOAD_DOWNLOAD_SHELF_MAC_H_
 #pragma once
 
 #import <Cocoa/Cocoa.h>
 
 #include "chrome/browser/download/download_shelf.h"
 
 class BaseDownloadItemModel;
 class CustomDrawButton;
 class DownloadItemMac;
 
 @class ShelfView;
 @class DownloadShelfController;
 
 // A class to bridge the chromium download shelf to mac gui. This is just a
 // wrapper class that forward everything to DownloadShelfController.
 
 class DownloadShelfMac : public DownloadShelf {
  public:
-  explicit DownloadShelfMac(Browser* browser,
-                            DownloadShelfController* controller);
+  DownloadShelfMac(Browser* browser, DownloadShelfController* controller);
 
   // DownloadShelf implementation.
   virtual void AddDownload(BaseDownloadItemModel* download_model);
   virtual bool IsShowing() const;
   virtual bool IsClosing() const;
   virtual void Show();
   virtual void Close();
   virtual Browser* browser() const;
 
  private:
   // The browser that owns this shelf.
   Browser* browser_;
 
   DownloadShelfController* shelf_controller_;  // weak, owns us
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_DOWNLOAD_DOWNLOAD_SHELF_MAC_H_