Revert "Add new atomic operations and use them in two places."

runtime/vm/os_thread.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/os_thread.h"
 
 #include "vm/atomic.h"
 #include "vm/lockers.h"
 #include "vm/log.h"
 #include "vm/thread_interrupter.h"
@@ skipping 85 matching lines @@
   }
   if (old == 0) {
     // We just decremented from 0, this means we've got a mismatched pair
     // of calls to EnableThreadInterrupts and DisableThreadInterrupts.
     FATAL("Invalid call to OSThread::EnableThreadInterrupts()");
   }
 }
 
 
 bool OSThread::ThreadInterruptsEnabled() {
-  return AtomicOperations::LoadAcquire(&thread_interrupt_disabled_) == 0;
+  return AtomicOperations::LoadRelaxed(&thread_interrupt_disabled_) == 0;
 }
 
 
 static void DeleteThread(void* thread) {
   delete reinterpret_cast<OSThread*>(thread);
 }
 
 
 void OSThread::InitOnce() {
   // Allocate the global OSThread lock.
@@ skipping 170 matching lines @@
 
 OSThread* OSThreadIterator::Next() {
   ASSERT(OSThread::thread_list_lock_ != NULL);
   ASSERT(OSThread::thread_list_lock_->IsOwnedByCurrentThread());
   OSThread* current = next_;
   next_ = next_->thread_list_next_;
   return current;
 }
 
 }  // namespace dart