Finish completeSweep before shutting down V8

third_party/WebKit/Source/platform/heap/ThreadState.h

 /*
  * Copyright (C) 2013 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 172 matching lines @@
     static void unlockThreadAttachMutex();
 
     // Initialize threading infrastructure. Should be called from the main
     // thread.
     static void init();
     static void shutdown();
     bool isTerminating() { return m_isTerminating; }
 
     static void attachMainThread();
     static void detachMainThread();
+    void stopMainThread();
 
     // Trace all persistent roots, called when marking the managed heap objects.
     static void visitPersistentRoots(Visitor*);
 
     // Trace all objects found on the stack, used when doing conservative GCs.
     static void visitStackRoots(Visitor*);
 
     // Associate ThreadState object with the current thread. After this
     // call thread can start using the garbage collected heap infrastructure.
     // It also has to periodically check for safepoints.
@@ skipping 220 matching lines @@
         m_orderedPreFinalizers.remove(PreFinalizer(self, &T::invokePreFinalizer));
     }
 
     void shouldFlushHeapDoesNotContainCache() { m_shouldFlushHeapDoesNotContainCache = true; }
 
     void registerTraceDOMWrappers(v8::Isolate* isolate, void (*traceDOMWrappers)(v8::Isolate*, Visitor*))
     {
         m_isolate = isolate;
         m_traceDOMWrappers = traceDOMWrappers;
     }
-    void unregisterTraceDOMWrappers()

[haraken, 2016/03/10 05:42:23]

Previously I mentioned that we need to clear m_traceDOMWrappers before detaching
the main thread, but I was wrong. I don't think we need it because Oilpan's GC
should not happen after stopMainThread is called.

-    {
-        m_isolate = nullptr;
-        m_traceDOMWrappers = nullptr;
-    }
 
     // By entering a gc-forbidden scope, conservative GCs will not
     // be allowed while handling an out-of-line allocation request.
     // Intended used when constructing subclasses of GC mixins, where
     // the object being constructed cannot be safely traced & marked
     // fully should a GC be allowed while its subclasses are being
     // constructed.
     void enterGCForbiddenScopeIfNeeded(GarbageCollectedMixinConstructorMarker* gcMixinMarker)
     {
         ASSERT(checkThread());
@@ skipping 262 matching lines @@
 
 template<> class ThreadStateFor<AnyThread> {
     STATIC_ONLY(ThreadStateFor);
 public:
     static ThreadState* state() { return ThreadState::current(); }
 };
 
 } // namespace blink
 
 #endif // ThreadState_h