Make ActiveScriptWrappable the GC mixin it is.

third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "wtf/HashSet.h"
 #include "wtf/ThreadSpecific.h"
 #include "wtf/Threading.h"
 
 namespace blink {
 
 namespace {
 
-using ActiveScriptWrappableSetType = HashSet<const ActiveScriptWrappable*>;
+using ActiveScriptWrappableSetType = PersistentHeapHashSet<WeakMember<const ActiveScriptWrappable>>;
 
 ActiveScriptWrappableSetType& activeScriptWrappables()
 {
     DEFINE_THREAD_SAFE_STATIC_LOCAL(ThreadSpecific<ActiveScriptWrappableSetType>, activeScriptWrappableSet, new ThreadSpecific<ActiveScriptWrappableSetType>());

[haraken, 2016/05/10 07:10:27]

Not directly related to this CL, shall we move the hash set to V8PerIsolateData?
V8PerIsolateData is to store per-isolate things like this.

[sof, 2016/05/10 15:46:04]

That would avoid ThreadSpecific<> , which would be a good thing overall. I can
try to followup.

+    if (!activeScriptWrappableSet.isSet())
+        activeScriptWrappableSet->registerAsStaticReference();
     return *activeScriptWrappableSet;
 }
 
 } // namespace
 
 ActiveScriptWrappable::ActiveScriptWrappable(ScriptWrappable* self)
     : m_scriptWrappable(self)
 {
     activeScriptWrappables().add(this);
 }
 
-ActiveScriptWrappable::~ActiveScriptWrappable()
-{
-    activeScriptWrappables().remove(this);
-}
-
 ScriptWrappable* ActiveScriptWrappable::toScriptWrappable() const
 {
     return m_scriptWrappable;
 }
 
 void ActiveScriptWrappable::traceActiveScriptWrappables(ScriptWrappableVisitor* visitor)
 {
     for (auto activeWrappable : activeScriptWrappables()) {
         if (!activeWrappable->hasPendingActivity())
             continue;
 
         visitor->traceWrappers(activeWrappable->toScriptWrappable());
     }
 }
 
 } // namespace blink