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

third_party/WebKit/Source/core/svg/animation/SVGSMILElement.cpp

 /*
  * Copyright (C) 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 63 matching lines @@
 };
 
 inline RepeatEvent* toRepeatEvent(Event* event)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!event || event->type() == "repeatn");
     return static_cast<RepeatEvent*>(event);
 }
 
 static SMILEventSender& smilEndEventSender()
 {
-    DEFINE_STATIC_LOCAL(Persistent<SMILEventSender>, sender, (SMILEventSender::create(EventTypeNames::endEvent)));
-    return *sender;
+    DEFINE_STATIC_LOCAL(SMILEventSender, sender, (SMILEventSender::create(EventTypeNames::endEvent)));
+    return sender;
 }
 
 static SMILEventSender& smilBeginEventSender()
 {
-    DEFINE_STATIC_LOCAL(Persistent<SMILEventSender>, sender, (SMILEventSender::create(EventTypeNames::beginEvent)));
-    return *sender;
+    DEFINE_STATIC_LOCAL(SMILEventSender, sender, (SMILEventSender::create(EventTypeNames::beginEvent)));
+    return sender;
 }
 
 static SMILEventSender& smilRepeatEventSender()
 {
-    DEFINE_STATIC_LOCAL(Persistent<SMILEventSender>, sender, (SMILEventSender::create(EventTypeNames::repeatEvent)));
-    return *sender;
+    DEFINE_STATIC_LOCAL(SMILEventSender, sender, (SMILEventSender::create(EventTypeNames::repeatEvent)));
+    return sender;
 }
 
 static SMILEventSender& smilRepeatNEventSender()
 {
-    DEFINE_STATIC_LOCAL(Persistent<SMILEventSender>, sender, (SMILEventSender::create(AtomicString("repeatn"))));
-    return *sender;
+    DEFINE_STATIC_LOCAL(SMILEventSender, sender, (SMILEventSender::create(AtomicString("repeatn"))));
+    return sender;
 }
 
 // This is used for duration type time values that can't be negative.
 static const double invalidCachedTime = -1.;
 
 class ConditionEventListener final : public EventListener {
 public:
     static ConditionEventListener* create(SVGSMILElement* animation, SVGSMILElement::Condition* condition)
     {
         return new ConditionEventListener(animation, condition);
@@ skipping 1112 matching lines @@
     m_nextProgressTime = calculateNextProgressTime(elapsed);
     return animationIsContributing;
 }
 
 void SVGSMILElement::notifyDependentsIntervalChanged()
 {
     ASSERT(m_interval.begin.isFinite());
     // |loopBreaker| is used to avoid infinite recursions which may be caused from:
     // |notifyDependentsIntervalChanged| -> |createInstanceTimesFromSyncbase| -> |add{Begin,End}Time| -> |{begin,end}TimeChanged| -> |notifyDependentsIntervalChanged|
     // |loopBreaker| is defined as a Persistent<HeapHashSet<Member<SVGSMILElement>>>. This won't cause leaks because it is guaranteed to be empty after the root |notifyDependentsIntervalChanged| has exited.
-    DEFINE_STATIC_LOCAL(Persistent<HeapHashSet<Member<SVGSMILElement>>>, loopBreaker, (new HeapHashSet<Member<SVGSMILElement>>()));
-    if (!loopBreaker->add(this).isNewEntry)
+    DEFINE_STATIC_LOCAL(HeapHashSet<Member<SVGSMILElement>>, loopBreaker, (new HeapHashSet<Member<SVGSMILElement>>));
+    if (!loopBreaker.add(this).isNewEntry)
         return;
 
     for (SVGSMILElement* element : m_syncBaseDependents)
         element->createInstanceTimesFromSyncbase(this);
 
-    loopBreaker->remove(this);
+    loopBreaker.remove(this);
 }
 
 void SVGSMILElement::createInstanceTimesFromSyncbase(SVGSMILElement* syncBase)
 {
     // FIXME: To be really correct, this should handle updating exising interval by changing
     // the associated times instead of creating new ones.
     for (unsigned n = 0; n < m_conditions.size(); ++n) {
         Condition* condition = m_conditions[n].get();
         if (condition->getType() == Condition::Syncbase && condition->syncBase() == syncBase) {
             ASSERT(condition->name() == "begin" || condition->name() == "end");
@@ skipping 114 matching lines @@
     visitor->trace(m_targetElement);
     visitor->trace(m_timeContainer);
     visitor->trace(m_conditions);
     visitor->trace(m_syncBaseDependents);
 #endif
     SVGElement::trace(visitor);
     SVGTests::trace(visitor);
 }
 
 } // namespace blink