Make progress in incremental marking if scavenge is delaying mark-sweep.

test/cctest/test-heap.cc

Index: test/cctest/test-heap.cc
diff --git a/test/cctest/test-heap.cc b/test/cctest/test-heap.cc
index 999e2c66518b010561440292419606b8816b08d6..d6f08c3eac2083ffeaedea105c7178cbcccfce86 100644
--- a/test/cctest/test-heap.cc
+++ b/test/cctest/test-heap.cc
@@ -1521,17 +1521,13 @@ TEST(InstanceOfStubWriteBarrier) {
 
   while (!Marking::IsBlack(Marking::MarkBitFrom(f->code())) &&
          !marking->IsStopped()) {
-    marking->Step(MB);
+    // Discard any pending GC requests otherwise we will get GC when we enter
+    // code below.
+    marking->Step(MB, IncrementalMarking::NO_GC_VIA_STACK_GUARD);
   }
 
   CHECK(marking->IsMarking());
 
-  // Discard any pending GC requests otherwise we will get GC when we enter
-  // code below.
-  if (ISOLATE->stack_guard()->IsGCRequest()) {
-    ISOLATE->stack_guard()->Continue(GC_REQUEST);
-  }
-
   {
     v8::HandleScope scope;
     v8::Handle<v8::Object> global = v8::Context::GetCurrent()->Global();