Use the incremental root marking visitor for overapproximating the weak closure

src/heap/incremental-marking.cc

Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc b/src/heap/incremental-marking.cc
index 76c05de6065be5da1c51e8a7f7f8894f1eed82fb..a60e5bc93dd93d41cee85d0ce03ee5619154d3d8 100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -559,6 +559,26 @@ void IncrementalMarking::StartMarking(CompactionFlag flag) {
 }
 
 
+void IncrementalMarking::MarkObjectGroups() {
+  DCHECK(FLAG_overapproximate_weak_closure);
+  DCHECK(!weak_closure_was_overapproximated_);
+
+  GCTracer::Scope gc_scope(heap_->tracer(),
+                           GCTracer::Scope::MC_INCREMENTAL_WEAKCLOSURE);
+
+  heap_->mark_compact_collector()->MarkImplicitRefGroups();

[jochen (gone - plz use gerrit), 2015/03/13 09:59:27]

this might be wrong too, as it just marks the objects. Guess it should just mark
white objects grey and push them...

+
+  IncrementalMarkingRootMarkingVisitor visitor(this);
+  heap_->isolate()->global_handles()->IterateObjectGroups(
+      &visitor, &MarkCompactCollector::IsUnmarkedHeapObjectWithHeap);
+
+  heap_->isolate()->global_handles()->RemoveImplicitRefGroups();
+  heap_->isolate()->global_handles()->RemoveObjectGroups();
+
+  weak_closure_was_overapproximated_ = true;
+}
+
+
 void IncrementalMarking::PrepareForScavenge() {
   if (!IsMarking()) return;
   NewSpacePageIterator it(heap_->new_space()->FromSpaceStart(),
@@ -777,7 +797,6 @@ void IncrementalMarking::OverApproximateWeakClosure() {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] requesting weak closure overapproximation.\n");
   }
-  set_should_hurry(true);
   request_type_ = OVERAPPROXIMATION;
   heap_->isolate()->stack_guard()->RequestGC();
 }