More style nits.

chrome/browser/gtk/external_protocol_dialog_gtk.h

 // Copyright (c) 2009 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_GTK_EXTERNAL_PROTOCOL_DIALOG_GTK_H_
 #define CHROME_BROWSER_GTK_EXTERNAL_PROTOCOL_DIALOG_GTK_H_
 
 #include "base/time.h"
 #include "googleurl/src/gurl.h"
 
 class TabContents;
 
 typedef struct _GtkWidget GtkWidget;
 
 class ExternalProtocolDialogGtk {
  public:
-  ExternalProtocolDialogGtk(const GURL& url);
+  explicit ExternalProtocolDialogGtk(const GURL& url);
 
  private:
   static void OnDialogResponse(GtkWidget* widget,
                                int response,
                                ExternalProtocolDialogGtk* dialog);
 
   GtkWidget* dialog_;
   GURL url_;
   base::Time creation_time_;
 };
 
 #endif  // CHROME_BROWSER_GTK_EXTERNAL_PROTOCOL_DIALOG_GTK_H_