Improve DEFINE_STATIC_LOCAL()'s handling of Blink GCed objects.

third_party/WebKit/Source/core/css/CSSDefaultStyleSheets.cpp

 /*
  * 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 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 27 matching lines @@
 #include "core/layout/LayoutTheme.h"
 #include "platform/PlatformResourceLoader.h"
 #include "wtf/LeakAnnotations.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 CSSDefaultStyleSheets& CSSDefaultStyleSheets::instance()
 {
-    DEFINE_STATIC_LOCAL(Persistent<CSSDefaultStyleSheets>, cssDefaultStyleSheets, (new CSSDefaultStyleSheets()));
-    return *cssDefaultStyleSheets;
+    DEFINE_STATIC_LOCAL(CSSDefaultStyleSheets, cssDefaultStyleSheets, (new CSSDefaultStyleSheets));
+    return cssDefaultStyleSheets;
 }
 
 static const MediaQueryEvaluator& screenEval()
 {
-    DEFINE_STATIC_LOCAL(Persistent<MediaQueryEvaluator>, staticScreenEval, (new MediaQueryEvaluator("screen")));
-    return *staticScreenEval;
+    DEFINE_STATIC_LOCAL(MediaQueryEvaluator, staticScreenEval, (new MediaQueryEvaluator("screen")));
+    return staticScreenEval;
 }
 
 static const MediaQueryEvaluator& printEval()
 {
-    DEFINE_STATIC_LOCAL(Persistent<MediaQueryEvaluator>, staticPrintEval, (new MediaQueryEvaluator("print")));
-    return *staticPrintEval;
+    DEFINE_STATIC_LOCAL(MediaQueryEvaluator, staticPrintEval, (new MediaQueryEvaluator("print")));
+    return staticPrintEval;
 }
 
 static RawPtr<StyleSheetContents> parseUASheet(const String& str)
 {
     RawPtr<StyleSheetContents> sheet = StyleSheetContents::create(CSSParserContext(UASheetMode, 0));
     sheet->parseString(str);
     // User Agent stylesheets are parsed once for the lifetime of the renderer
     // process and are intentionally leaked.
     LEAK_SANITIZER_IGNORE_OBJECT(sheet.get());
     return sheet.release();
@@ skipping 119 matching lines @@
     visitor->trace(m_defaultStyleSheet);
     visitor->trace(m_mobileViewportStyleSheet);
     visitor->trace(m_quirksStyleSheet);
     visitor->trace(m_svgStyleSheet);
     visitor->trace(m_mathmlStyleSheet);
     visitor->trace(m_mediaControlsStyleSheet);
     visitor->trace(m_fullscreenStyleSheet);
 }
 
 } // namespace blink