Make ActiveScriptWrappable the GC mixin it is.

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

Index: third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp b/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp
index fe1e2109876e1a32ed618ffe409fb4c65694ac2f..088db3b2fe14cd47caec48ffaa62f761c20bbaa7 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.cpp
@@ -13,11 +13,13 @@ 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;
 }
 
@@ -29,11 +31,6 @@ ActiveScriptWrappable::ActiveScriptWrappable(ScriptWrappable* self)
     activeScriptWrappables().add(this);
 }
 
-ActiveScriptWrappable::~ActiveScriptWrappable()
-{
-    activeScriptWrappables().remove(this);
-}
-
 ScriptWrappable* ActiveScriptWrappable::toScriptWrappable() const
 {
     return m_scriptWrappable;