Refactoring: Make ~CSSStyleSheetResource empty.

Source/core/fetch/CSSStyleSheetResource.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
 
     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
@@ skipping 31 matching lines @@
 {
     DEFINE_STATIC_LOCAL(const AtomicString, acceptCSS, ("text/css,*/*;q=0.1", AtomicString::ConstructFromLiteral));
 
     // Prefer text/css but accept any type (dell.com serves a stylesheet
     // as text/html; see <http://bugs.webkit.org/show_bug.cgi?id=11451>).
     setAccept(acceptCSS);
 }
 
 CSSStyleSheetResource::~CSSStyleSheetResource()
 {
+    // Make sure dispose() was cllaed before destruction.
+    ASSERT(!m_parsedStyleSheetCache);
+}
+
+void CSSStyleSheetResource::dispose()
+{
     if (m_parsedStyleSheetCache)
         m_parsedStyleSheetCache->removedFromMemoryCache();
+    m_parsedStyleSheetCache.clear();
 }
 
 void CSSStyleSheetResource::didAddClient(ResourceClient* c)
 {
     ASSERT(c->resourceClientType() == StyleSheetResourceClient::expectedType());
     // Resource::didAddClient() must be before setCSSStyleSheet(),
     // because setCSSStyleSheet() may cause scripts to be executed, which could destroy 'c' if it is an instance of HTMLLinkElement.
     // see the comment of HTMLLinkElement::setCSSStyleSheet.
     Resource::didAddClient(c);
 
@@ skipping 96 matching lines @@
 
     if (m_parsedStyleSheetCache)
         m_parsedStyleSheetCache->removedFromMemoryCache();
     m_parsedStyleSheetCache = sheet;
     m_parsedStyleSheetCache->addedToMemoryCache();
 
     setDecodedSize(m_parsedStyleSheetCache->estimatedSizeInBytes());
 }
 
 }