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

third_party/WebKit/Source/core/dom/ContextFeatures.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 11 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/dom/ContextFeatures.h"
 
 #include "core/dom/Document.h"
 #include "core/page/Page.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "wtf/StdLibExtras.h"
 
 namespace blink {
 
 PassOwnPtr<ContextFeaturesClient> ContextFeaturesClient::empty()
 {
     return adoptPtr(new ContextFeaturesClient());
 }
 
 const char* ContextFeatures::supplementName()
 {
     return "ContextFeatures";
 }
 
-ContextFeatures* ContextFeatures::defaultSwitch()
+ContextFeatures& ContextFeatures::defaultSwitch()
 {
-    DEFINE_STATIC_REF_WILL_BE_PERSISTENT(ContextFeatures, instance, (ContextFeatures::create(ContextFeaturesClient::empty())));
+    DEFINE_STATIC_LOCAL(ContextFeatures, instance, (ContextFeatures::create(ContextFeaturesClient::empty())));
     return instance;
 }
 
 bool ContextFeatures::pagePopupEnabled(Document* document)
 {
     if (!document)
         return false;
     return document->contextFeatures().isEnabled(document, PagePopup, false);
 }
 
@@ skipping 12 matching lines @@
 
 void provideContextFeaturesToDocumentFrom(Document& document, Page& page)
 {
     ContextFeatures* provided = static_cast<ContextFeatures*>(Supplement<Page>::from(page, ContextFeatures::supplementName()));
     if (!provided)
         return;
     document.setContextFeatures(*provided);
 }
 
 } // namespace blink