Revert 78101 - Merge r76728, crbug 68263

WebCore/css/CSSMediaRule.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006 Apple Computer, Inc.
  * Copyright (C) 2006 Samuel Weinig (sam@webkit.org)
  *
  * 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.
@@ skipping 70 matching lines @@
         // HIERARCHY_REQUEST_ERR: Raised if the rule cannot be inserted at the specified
         // index, e.g., if an @import rule is inserted after a standard rule set or other
         // at-rule.
         ec = HIERARCHY_REQUEST_ERR;
         return 0;
     }
 
     newRule->setParent(this);
     unsigned returnedIndex = m_lstCSSRules->insertRule(newRule.get(), index);
 
-    if (stylesheet())
-        stylesheet()->styleSheetChanged();
+    // stylesheet() can only return 0 for computed style declarations.
+    stylesheet()->styleSheetChanged();
 
     return returnedIndex;
 }
 
 void CSSMediaRule::deleteRule(unsigned index, ExceptionCode& ec)
 {
     if (index >= m_lstCSSRules->length()) {
         // INDEX_SIZE_ERR: Raised if the specified index does not correspond to a
         // rule in the media rule list.
         ec = INDEX_SIZE_ERR;
         return;
     }
 
     m_lstCSSRules->deleteRule(index);
 
-    if (stylesheet())
-        stylesheet()->styleSheetChanged();
+    // stylesheet() can only return 0 for computed style declarations.
+    stylesheet()->styleSheetChanged();
 }
 
 String CSSMediaRule::cssText() const
 {
     String result = "@media ";
     if (m_lstMedia) {
         result += m_lstMedia->mediaText();
         result += " ";
     }
     result += "{ \n";
 
     if (m_lstCSSRules) {
         unsigned len = m_lstCSSRules->length();
         for (unsigned i = 0; i < len; i++) {
             result += "  ";
             result += m_lstCSSRules->item(i)->cssText();
             result += "\n";
         }
     }
 
     result += "}";
     return result;
 }
 
 } // namespace WebCore