Implement a 2-pass heap verification algorithm.

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 VM_PAGES_H_
 #define VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
@@ skipping 169 matching lines @@
   RawObject* FindObject(FindObjectVisitor* visitor) const;
 
   // Collect the garbage in the page space using mark-sweep.
   void MarkSweep(bool invoke_api_callbacks);
 
   static HeapPage* PageFor(RawObject* raw_obj) {
     return reinterpret_cast<HeapPage*>(
         RawObject::ToAddr(raw_obj) & ~(kPageSize -1));
   }
 
+  void StartEndAddress(uword* start, uword* end) const;
+
   void EnableGrowthControl() {
     page_space_controller_.Enable();
   }
 
  private:
   static const intptr_t kAllocatablePageSize = kPageSize - sizeof(HeapPage);
 
   void AllocatePage();
   void FreePage(HeapPage* page, HeapPage* previous_page);
   HeapPage* AllocateLargePage(intptr_t size);
@@ skipping 38 matching lines @@
   bool sweeping_;
 
   PageSpaceController page_space_controller_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_