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

runtime/vm/gc_marker.cc

 // 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.
 
 #include "vm/gc_marker.h"
 
 #include "vm/allocation.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
@@ skipping 287 matching lines @@
   }
 
   void VisitingOldObject(RawObject* obj) {
     ASSERT((obj == NULL) || obj->IsOldObject());
     visiting_old_object_ = obj;
   }
 
  private:
   void PushMarked(RawObject* raw_obj) {
     ASSERT(raw_obj->IsHeapObject());
-    ASSERT((FLAG_verify_before_gc || FLAG_verify_before_gc)
+    ASSERT((FLAG_verify_gc_contains)
                ? page_space_->Contains(RawObject::ToAddr(raw_obj))
                : true);
 
     // Push the marked object on the marking stack.
     ASSERT(raw_obj->IsMarked());
     // We acquired the mark bit => no other task is modifying the header.
     // TODO(koda): For concurrent mutator, this needs synchronization. Consider
     // clearing these bits already in the CAS for the mark bit.
     raw_obj->ClearRememberedBitUnsynchronized();
     work_list_.Push(raw_obj);
@@ skipping 464 matching lines @@
       // Phase 3: Finalize results from all markers (detach code, etc.).
       barrier.Exit();
     }
     ProcessWeakTables(page_space);
     ProcessObjectIdTable(isolate);
   }
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart