1. Added new flag verify_gc_contains and moved all the asserts that do a

runtime/vm/pages.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_PAGES_H_
 #define RUNTIME_VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/lockers.h"
@@ skipping 209 matching lines @@
   void UpdateMaxUsed();
 
   int64_t ExternalInWords() const { return usage_.external_in_words; }
   SpaceUsage GetCurrentUsage() const {
     MutexLocker ml(pages_lock_);
     return usage_;
   }
 
   bool Contains(uword addr) const;
   bool Contains(uword addr, HeapPage::PageType type) const;
+  bool DataContains(uword addr) const;
   bool IsValidAddress(uword addr) const { return Contains(addr); }
 
   void VisitObjects(ObjectVisitor* visitor) const;
   void VisitObjectsNoEmbedderPages(ObjectVisitor* visitor) const;
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
   RawObject* FindObject(FindObjectVisitor* visitor,
                         HeapPage::PageType type) const;
 
   // Checks if enough time has elapsed since the last attempt to collect
@@ skipping 183 matching lines @@
   friend class HeapIterationScope;
   friend class PageSpaceController;
   friend class SweeperTask;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_PAGES_H_