[heap] Implement concurrent marking boilerplate.

test/cctest/heap/test-concurrent-marking.cc

+// Copyright 2017 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 <stdlib.h>
+
+#include "src/v8.h"
+
+#include "src/heap/concurrent-marking.h"
+#include "src/heap/heap-inl.h"
+#include "src/heap/heap.h"
+#include "test/cctest/cctest.h"
+#include "test/cctest/heap/heap-utils.h"
+
+namespace v8 {
+namespace internal {
+TEST(ConcurrentMarking) {
+  i::FLAG_concurrent_marking = true;
+  CcTest::InitializeVM();
+  Heap* heap = CcTest::heap();
+  ConcurrentMarking* concurrent_marking = new ConcurrentMarking(heap);
+  for (int i = 0; i < 10; i++) {
+    concurrent_marking->EnqueueObject(heap->undefined_value());
+  }
+  concurrent_marking->StartMarkingTasks(3);
+  while (!concurrent_marking->IsQueueEmpty()) {
+  }
+  concurrent_marking->WaitForTasksToComplete();
+  delete concurrent_marking;
+}
+
+}  // namespace internal
+}  // namespace v8