Simplify ownership of a ThreadState's interruptors.

Source/platform/heap/SafePoint.cpp

 // Copyright 2015 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 "config.h"
 #include "platform/heap/SafePoint.h"
 
 #include "wtf/Atomics.h"
 
 namespace blink {
@@ skipping 27 matching lines @@
     ThreadState::AttachedThreadStateSet& threads = ThreadState::attachedThreads();
 
     MutexLocker locker(m_mutex);
     atomicAdd(&m_unparkedThreadCount, threads.size());
     releaseStore(&m_canResume, 0);
 
     for (ThreadState* state : threads) {
         if (state == current)
             continue;
 
-        for (ThreadState::Interruptor* interruptor : state->interruptors())
+        for (auto& interruptor : state->interruptors())
             interruptor->requestInterrupt();
     }
 
     while (acquireLoad(&m_unparkedThreadCount) > 0) {
         double expirationTime = currentTime() + lockingTimeout();
         if (!m_parked.timedWait(m_mutex, expirationTime)) {
             // One of the other threads did not return to a safepoint within the maximum
             // time we allow for threads to be parked. Abandon the GC and resume the
             // currently parked threads.
             resumeOthers(true);
@@ skipping 72 matching lines @@
     // If no other thread is waiting for other threads to park then
     // this counter can be negative: if N threads are at safe-points
     // the counter will be -N.
     if (!atomicDecrement(&m_unparkedThreadCount)) {
         MutexLocker locker(m_mutex);
         m_parked.signal(); // Safe point reached.
     }
 }
 
 } // namespace blink