Added parallel marking threads.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 4dc4a95c8de2ab9b830c365a4b498fffb06e7d38..bdd4785e3e729368ab1c6bf297e48457f9b5c6b4 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -37,6 +37,7 @@
 #include "ic-inl.h"
 #include "incremental-marking.h"
 #include "mark-compact.h"
+#include "marking-thread.h"
 #include "objects-visiting.h"
 #include "objects-visiting-inl.h"
 #include "stub-cache.h"
@@ -540,6 +541,20 @@ bool MarkCompactCollector::AreSweeperThreadsActivated() {
 }
 
 
+void MarkCompactCollector::MarkInParallel() {
+  for (int i = 0; i < FLAG_marking_threads; i++) {
+    heap()->isolate()->marking_threads()[i]->StartMarking();
+  }
+}
+
+
+void MarkCompactCollector::WaitUntilMarkingCompleted() {
+  for (int i = 0; i < FLAG_marking_threads; i++) {
+    heap()->isolate()->marking_threads()[i]->WaitForMarkingThread();
+  }
+}
+
+
 bool Marking::TransferMark(Address old_start, Address new_start) {
   // This is only used when resizing an object.
   ASSERT(MemoryChunk::FromAddress(old_start) ==