Attempt no. 3 to fix Heap::IsHeapIterable and HeapIterator

test/cctest/test-heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 872 matching lines @@
     CHECK_EQ(length, ascii_str->length());
     DeleteArray(non_ascii);
     DeleteArray(ascii);
   }
 }
 
 
 static int ObjectsFoundInHeap(Heap* heap, Handle<Object> objs[], int size) {
   // Count the number of objects found in the heap.
   int found_count = 0;
-  heap->EnsureHeapIsIterable();
   HeapIterator iterator(heap);
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     for (int i = 0; i < size; i++) {
       if (*objs[i] == obj) {
         found_count++;
       }
     }
   }
   return found_count;
 }
@@ skipping 718 matching lines @@
   // Waiting for sweeper threads should not change heap size.
   if (collector->IsConcurrentSweepingInProgress()) {
     collector->WaitUntilSweepingCompleted();
   }
   CHECK_EQ(initial_size, static_cast<int>(CcTest::heap()->SizeOfObjects()));
 }
 
 
 TEST(TestSizeOfObjectsVsHeapIteratorPrecision) {
   CcTest::InitializeVM();
-  CcTest::heap()->EnsureHeapIsIterable();
+  HeapIterator iterator(CcTest::heap());
   intptr_t size_of_objects_1 = CcTest::heap()->SizeOfObjects();
-  HeapIterator iterator(CcTest::heap());
   intptr_t size_of_objects_2 = 0;
   for (HeapObject* obj = iterator.next();
        obj != NULL;
        obj = iterator.next()) {
     if (!obj->IsFreeSpace()) {
       size_of_objects_2 += obj->Size();
     }
   }
   // Delta must be within 5% of the larger result.
   // TODO(gc): Tighten this up by distinguishing between byte
@@ skipping 2599 matching lines @@
       "array;");
 
   Handle<JSObject> o =
       v8::Utils::OpenHandle(*v8::Handle<v8::Object>::Cast(result));
   CHECK(heap->InOldPointerSpace(o->elements()));
   CHECK(heap->InOldPointerSpace(*o));
   Page* page = Page::FromAddress(o->elements()->address());
   CHECK(page->WasSwept() ||
         Marking::IsBlack(Marking::MarkBitFrom(o->elements())));
 }