Revert "Pull from svn bleeding_edge@3716"

This reverts commit 888f6729be6a6f6fbe246cb5a9f122e2dbe455b7.

(Waiting until v8 issue 554101 is in v8 rather than patching it straight into
android)
diff --git a/src/heap.h b/src/heap.h
index 0dd20c0..1f04444 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -690,8 +690,6 @@
   static void IterateRoots(ObjectVisitor* v, VisitMode mode);
   // Iterates over all strong roots in the heap.
   static void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
-  // Iterates over all the other roots in the heap.
-  static void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
 
   // Iterates remembered set of an old space.
   static void IterateRSet(PagedSpace* space, ObjectSlotCallback callback);
@@ -1292,6 +1290,7 @@
   explicit HeapIterator();
   virtual ~HeapIterator();
 
+  bool has_next();
   HeapObject* next();
   void reset();