Make assertion scopes thread safe.

src/marking-thread.cc

 // Copyright 2013 the V8 project authors. 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 34 matching lines @@
   NoBarrier_Store(&stop_thread_, static_cast<AtomicWord>(false));
   id_ = NoBarrier_AtomicIncrement(&id_counter_, 1);
 }
 
 
 Atomic32 MarkingThread::id_counter_ = -1;
 
 
 void MarkingThread::Run() {
   Isolate::SetIsolateThreadLocals(isolate_, NULL);
+  DisallowHeapAllocation no_allocation;
+  DisallowHandleAllocation no_handles;
+  DisallowHandleDereference no_deref;
 
   while (true) {
     start_marking_semaphore_->Wait();
 
     if (Acquire_Load(&stop_thread_)) {
       stop_semaphore_->Signal();
       return;
     }
 
     end_marking_semaphore_->Signal();
@@ skipping 11 matching lines @@
 void MarkingThread::StartMarking() {
   start_marking_semaphore_->Signal();
 }
 
 
 void MarkingThread::WaitForMarkingThread() {
   end_marking_semaphore_->Wait();
 }
 
 } }  // namespace v8::internal