Remove mediawiki stylesheet hack

Source/core/css/StyleSheetContents.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 275 matching lines @@
     // If we're loading a stylesheet cross-origin, and the MIME type is not standard, require the CSS
     // to at least start with a syntactically valid CSS rule.
     // This prevents an attacker playing games by injecting CSS strings into HTML, XML, JSON, etc. etc.
     if (!hasValidMIMEType && !hasSyntacticallyValidCSSHeader()) {
         bool isCrossOriginCSS = !securityOrigin || !securityOrigin->canRequest(baseURL());
         if (isCrossOriginCSS) {
             clearRules();
             return;
         }
     }
-    if (!quirksMode && m_parserContext.needsSiteSpecificQuirks) {
-        // Work around <https://bugs.webkit.org/show_bug.cgi?id=28350>.
-        DEFINE_STATIC_LOCAL(const String, mediaWikiKHTMLFixesStyleSheet, ("/* KHTML fix stylesheet */\n/* work around the horizontal scrollbars */\n#column-content { margin-left: 0; }\n\n"));
-        // There are two variants of KHTMLFixes.css. One is equal to mediaWikiKHTMLFixesStyleSheet,
-        // while the other lacks the second trailing newline.
-        if (baseURL().string().endsWith("/KHTMLFixes.css") && !sheetText.isNull() && mediaWikiKHTMLFixesStyleSheet.startsWith(sheetText)
-            && sheetText.length() >= mediaWikiKHTMLFixesStyleSheet.length() - 1)
-            clearRules();
-    }
 }
 
 bool StyleSheetContents::parseString(const String& sheetText)
 {
     return parseStringAtPosition(sheetText, TextPosition::minimumPosition(), false);
 }
 
 bool StyleSheetContents::parseStringAtPosition(const String& sheetText, const TextPosition& startPosition, bool createdByParser)
 {
     CSSParser p(parserContext(), UseCounter::getFrom(this));
@@ skipping 189 matching lines @@
     m_isInMemoryCache = false;
 }
 
 void StyleSheetContents::shrinkToFit()
 {
     m_importRules.shrinkToFit();
     m_childRules.shrinkToFit();
 }
 
 }