Missing explicit keyword in ctor of FooImpl.h

Source/web/WebPopupMenuImpl.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 95 matching lines @@
     void handleMouseDoubleClick(const WebMouseEvent&);
     void handleMouseWheel(const WebMouseWheelEvent&);
     bool handleGestureEvent(const WebGestureEvent&);
     bool handleTouchEvent(const WebTouchEvent&);
     bool handleKeyEvent(const WebKeyboardEvent&);
 
    protected:
     friend class WebPopupMenu; // For WebPopupMenu::create.
     friend class WTF::RefCounted<WebPopupMenuImpl>;
 
-    WebPopupMenuImpl(WebWidgetClient*);
+    explicit WebPopupMenuImpl(WebWidgetClient*);
     ~WebPopupMenuImpl();
 
     // blink::HostWindow methods:
     virtual void invalidateContentsAndRootView(const blink::IntRect&) OVERRIDE FINAL;
     virtual void invalidateContentsForSlowScroll(const blink::IntRect&) OVERRIDE FINAL;
     virtual void scheduleAnimation() OVERRIDE FINAL;
     virtual void scroll(const blink::IntRect& clipRect) OVERRIDE FINAL;
     virtual blink::IntRect rootViewToScreen(const blink::IntRect&) const OVERRIDE FINAL;
     virtual WebScreenInfo screenInfo() const OVERRIDE FINAL;
 
@@ skipping 14 matching lines @@
 };
 
 DEFINE_TYPE_CASTS(WebPopupMenuImpl, WebWidget, widget, widget->isPopupMenu(), widget.isPopupMenu());
 // WebPopupMenuImpl is the only implementation of FramelessScrollViewClient, so
 // no need for further checking.
 DEFINE_TYPE_CASTS(WebPopupMenuImpl, blink::FramelessScrollViewClient, client, true, true);
 
 } // namespace blink
 
 #endif