Remove unnecessary explicit keywords from a constructor with more than one parameters in css direct…

Source/core/css/SelectorChecker.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 28 matching lines @@
 class Element;
 class RenderScrollbar;
 class RenderStyle;
 
 class SelectorChecker {
     WTF_MAKE_NONCOPYABLE(SelectorChecker);
 public:
     enum Match { SelectorMatches, SelectorFailsLocally, SelectorFailsAllSiblings, SelectorFailsCompletely };
     enum VisitedMatchType { VisitedMatchDisabled, VisitedMatchEnabled };
     enum Mode { ResolvingStyle = 0, CollectingStyleRules, CollectingCSSRules, QueryingRules, SharingRules };
-    explicit SelectorChecker(Document&, Mode);
+    SelectorChecker(Document&, Mode);
 
     struct SelectorCheckingContext {
         STACK_ALLOCATED();
     public:
         // Initial selector constructor
         SelectorCheckingContext(const CSSSelector& selector, Element* element, VisitedMatchType visitedMatchType)
             : selector(&selector)
             , element(element)
             , previousElement(nullptr)
             , scope(nullptr)
@@ skipping 115 matching lines @@
 }
 
 inline bool SelectorChecker::isHostInItsShadowTree(const Element& element, const ContainerNode* scope)
 {
     return scope && scope->isInShadowTree() && scope->shadowHost() == element;
 }
 
 }
 
 #endif