[heap] Do not invoke GC to make heap iterable.

src/profiler/heap-snapshot-generator.cc

Index: src/profiler/heap-snapshot-generator.cc
diff --git a/src/profiler/heap-snapshot-generator.cc b/src/profiler/heap-snapshot-generator.cc
index e67acef268f1fdc340425ac07f59182287f3232c..f8cf4f7e4d82aed200fe5238d55c21f9c03292f2 100644
--- a/src/profiler/heap-snapshot-generator.cc
+++ b/src/profiler/heap-snapshot-generator.cc
@@ -478,8 +478,8 @@ void HeapObjectsMap::UpdateHeapObjectsMap() {
     PrintF("Begin HeapObjectsMap::UpdateHeapObjectsMap. map has %d entries.\n",
            entries_map_.occupancy());
   }
-  heap_->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "HeapObjectsMap::UpdateHeapObjectsMap");
+  heap_->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask,
+                           "HeapObjectsMap::UpdateHeapObjectsMap");
   HeapIterator iterator(heap_);
   for (HeapObject* obj = iterator.next();
        obj != NULL;
@@ -2505,12 +2505,10 @@ bool HeapSnapshotGenerator::GenerateSnapshot() {
   // full GC is reachable from the root when computing dominators.
   // This is not true for weakly reachable objects.
   // As a temporary solution we call GC twice.
-  heap_->CollectAllGarbage(
-      Heap::kMakeHeapIterableMask,
-      "HeapSnapshotGenerator::GenerateSnapshot");
-  heap_->CollectAllGarbage(
-      Heap::kMakeHeapIterableMask,
-      "HeapSnapshotGenerator::GenerateSnapshot");
+  heap_->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask,
+                           "HeapSnapshotGenerator::GenerateSnapshot");
+  heap_->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask,
+                           "HeapSnapshotGenerator::GenerateSnapshot");
 
 #ifdef VERIFY_HEAP
   Heap* debug_heap = heap_;