Make |Heap::findGCInfo()| threadsafe.

Source/platform/heap/ThreadState.h

Index: Source/platform/heap/ThreadState.h
diff --git a/Source/platform/heap/ThreadState.h b/Source/platform/heap/ThreadState.h
index f0eea36a4881e4fa2076651b79fb403f1fed3cdd..bdd6c0f2fa0fbd1843a4be13ba38ab629ec1e6a4 100644
--- a/Source/platform/heap/ThreadState.h
+++ b/Source/platform/heap/ThreadState.h
@@ -504,6 +504,8 @@ public:
     HeapStats& stats() { return m_stats; }
     HeapStats& statsAfterLastGC() { return m_statsAfterLastGC; }
 
+    static Mutex& threadAttachMutex();

[Mads Ager (chromium), 2014/06/06 06:54:01]

Instead of exposing this, can you move the code that does the iteration to
ThreadState?

Heap::findGCInfo(...)
{
  ...
  return ThreadState::findGCInfo();
}

?

[kouhei (in TOK), 2014/06/06 06:58:26]

Ack.

+
 private:
     explicit ThreadState();
     ~ThreadState();