[heap] Implement simple concurrent marking deque.

src/heap/incremental-marking.cc

 // 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.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/concurrent-marking.h"
@@ skipping 533 matching lines @@
 
   heap_->CompletelyClearInstanceofCache();
   heap_->isolate()->compilation_cache()->MarkCompactPrologue();
 
   // Mark strong roots grey.
   IncrementalMarkingRootMarkingVisitor visitor(this);
   heap_->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG);
 
   if (FLAG_concurrent_marking) {
     ConcurrentMarking* concurrent_marking = heap_->concurrent_marking();
-    marking_deque()->Iterate([concurrent_marking](HeapObject* obj) {
-      concurrent_marking->AddRoot(obj);
-    });
     concurrent_marking->StartTask();
   }
 
   // Ready to start incremental marking.
   if (FLAG_trace_incremental_marking) {
     heap()->isolate()->PrintWithTimestamp("[IncrementalMarking] Running\n");
   }
 }
 
 void IncrementalMarking::StartBlackAllocation() {
@@ skipping 599 matching lines @@
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 
 }  // namespace internal
 }  // namespace v8