[heap] Use RAIL mode for initial heap sizing

src/heap/incremental-marking-job.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_INCREMENTAL_MARKING_JOB_H_
 #define V8_HEAP_INCREMENTAL_MARKING_JOB_H_
 
+#include "src/base/atomic-utils.h"
 #include "src/cancelable-task.h"
 
 namespace v8 {
 namespace internal {
 
 class Heap;
 class Isolate;
 
 // The incremental marking job uses platform tasks to perform incremental
 // marking steps. The job posts a foreground task that makes a small (~1ms)
 // step and posts another task until the marking is completed.
 class IncrementalMarkingJob {
  public:
   class Task : public CancelableTask {
    public:
     explicit Task(Isolate* isolate, IncrementalMarkingJob* job)
         : CancelableTask(isolate), job_(job) {}
     static void Step(Heap* heap);
     // CancelableTask overrides.
     void RunInternal() override;
 
    private:
     IncrementalMarkingJob* job_;
   };
 
   IncrementalMarkingJob() : task_pending_(false) {}
 
-  bool TaskPending() { return task_pending_; }
-
   void Start(Heap* heap);
 
   void NotifyTask();
 
   void ScheduleTask(Heap* heap);
 
  private:
-  bool task_pending_;
+  base::AtomicValue<bool> task_pending_;
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_JOB_H_