[vm, gc] Require a safepoint for heap iteration.

runtime/vm/class_table.cc

 // Copyright (c) 2012, 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/class_table.h"
 
 #include "vm/atomic.h"
 #include "vm/flags.h"
 #include "vm/freelist.h"
 #include "vm/growable_array.h"
@@ skipping 187 matching lines @@
   table_[index] = cls.raw();
 }
 
 #if defined(DEBUG)
 void ClassTable::Unregister(intptr_t index) {
   table_[index] = 0;
 }
 #endif
 
 void ClassTable::Remap(intptr_t* old_to_new_cid) {
-  ASSERT(Thread::Current()->no_safepoint_scope_depth() > 0);
+  ASSERT(Thread::Current()->IsAtSafepoint());
   intptr_t num_cids = NumCids();
   RawClass** cls_by_old_cid = new RawClass*[num_cids];
   for (intptr_t i = 0; i < num_cids; i++) {
     cls_by_old_cid[i] = table_[i];
   }
   for (intptr_t i = 0; i < num_cids; i++) {
     table_[old_to_new_cid[i]] = cls_by_old_cid[i];
   }
   delete[] cls_by_old_cid;
 }
@@ skipping 328 matching lines @@
 
 void ClassTable::UpdateLiveNew(intptr_t cid, intptr_t size) {
   ClassHeapStats* stats = PreliminaryStatsAt(cid);
   ASSERT(stats != NULL);
   ASSERT(size >= 0);
   stats->post_gc.AddNew(size);
 }
 #endif  // !PRODUCT
 
 }  // namespace dart