Make the implicit constructor private for zone, handlescope and nohandlescope classes.

vm/zone.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_ZONE_H_
 #define VM_ZONE_H_
 
 #include "vm/allocation.h"
 #include "vm/handles.h"
 #include "vm/memory_region.h"
@@ skipping 116 matching lines @@
   void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
  private:
   BaseZone zone_;
 
   // Structure for managing handles allocation.
   VMHandles handles_;
 
   // Used for chaining zones in order to allow unwinding of stacks.
   Zone* previous_;
-  DISALLOW_COPY_AND_ASSIGN(Zone);
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Zone);
 };
 
 
 inline uword BaseZone::Allocate(intptr_t size) {
   ASSERT(size >= 0);
 
   // Round up the requested size to fit the alignment.
   size = Utils::RoundUp(size, kAlignment);
 
   // Check if the requested size is available without expanding.
   uword result;
   intptr_t free_size = (limit_ - position_);
   if (free_size >= size) {
     result = position_;
     position_ += size;
   } else {
     result = AllocateExpand(size);
   }
 
   // Check that the result has the proper alignment and return it.
   ASSERT(Utils::IsAligned(result, kAlignment));
   return result;
 }
 
 }  // namespace dart
 
 #endif  // VM_ZONE_H_