Remove explicit keyword from multi-argument constructors

chrome/browser/ui/gtk/infobars/extension_infobar_gtk.h

 // Copyright (c) 2011 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_GTK_INFOBARS_EXTENSION_INFOBAR_GTK_H_
 #define CHROME_BROWSER_UI_GTK_INFOBARS_EXTENSION_INFOBAR_GTK_H_
 #pragma once
 
 #include "chrome/browser/extensions/extension_infobar_delegate.h"
 #include "chrome/browser/extensions/image_loading_tracker.h"
 #include "chrome/browser/ui/gtk/extensions/extension_view_gtk.h"
 #include "chrome/browser/ui/gtk/infobars/infobar_gtk.h"
 #include "ui/gfx/gtk_util.h"
 
 class ExtensionInfobarDelegate;
 class ExtensionResource;
 class ExtensionViewGtk;
 
 class ExtensionInfoBarGtk : public InfoBarGtk,
                             public ImageLoadingTracker::Observer,
                             public ExtensionViewGtk::Container {
  public:
-  explicit ExtensionInfoBarGtk(TabContentsWrapper* owner,
-                               ExtensionInfoBarDelegate* delegate);
+  ExtensionInfoBarGtk(TabContentsWrapper* owner,
+                      ExtensionInfoBarDelegate* delegate);
   virtual ~ExtensionInfoBarGtk();
 
   // Overridden from ImageLoadingTracker::Observer:
   virtual void OnImageLoaded(
       SkBitmap* image, const ExtensionResource& resource, int index);
 
   // ExtensionViewGtk::Container implementation
   virtual void OnExtensionPreferredSizeChanged(ExtensionViewGtk* view,
                                                const gfx::Size& new_size);
 
  private:
   // Build the widgets of the Infobar.
   void BuildWidgets();
 
   CHROMEGTK_CALLBACK_1(ExtensionInfoBarGtk, void, OnSizeAllocate,
                        GtkAllocation*);
 
   ImageLoadingTracker tracker_;
 
   ExtensionInfoBarDelegate* delegate_;
 
   ExtensionViewGtk* view_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionInfoBarGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_INFOBARS_EXTENSION_INFOBAR_GTK_H_