Move Zone's destructor out of a header file.

runtime/vm/megamorphic_cache_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/megamorphic_cache_table.h"
 
 #include <stdlib.h>
-#include "vm/handles_impl.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 RawMegamorphicCache* MegamorphicCacheTable::Lookup(Isolate* isolate,
                                                    const String& name,
                                                    const Array& descriptor) {
@@ skipping 127 matching lines @@
     cumulative_entries += probe_counts[i];
     OS::Print("Megamorphic probe %" Pd ": %" Pd " (%lf)\n",
               i, probe_counts[i],
               static_cast<double>(cumulative_entries) /
               static_cast<double>(entry_count));
   }
   delete[] probe_counts;
 }
 
 }  // namespace dart