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

vm/handles.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_HANDLES_H_
 #define VM_HANDLES_H_
 
 #include "vm/allocation.h"
 
 namespace dart {
 
 // Handles are used in the Dart Virtual Machine to ensure that access
 // to dart objects in the virtual machine code is done in a
 // Garbage Collection safe manner.
 //
 // The class Handles is the basic type that implements creation of handles and
 // manages their life cycle (allocated either in the current zone or
 // current handle scope).
 // The two forms of handle allocation are:
 // - allocation of handles in the current zone (Handle::AllocateZoneHandle).
 //   Handles allocated in this manner are destroyed when the zone is destroyed.
 // - allocation of handles in a scoped manner (Handle::AllocateHandle).
-//   A new scope can be started using HANDLESCOPE().
+//   A new scope can be started using HANDLESCOPE(isolate).
 //   Handles allocated in this manner are destroyed when the HandleScope
 //   object is destroyed.
 // Code that uses scoped handles typically looks as follows:
 //   {
 //     HANDLESCOPE(isolate);
 //     const String& str = String::Handle(String::New("abc"));
 //     .....
 //     .....
 //   }
 // Code that uses zone handles typically looks as follows:
@@ skipping 219 matching lines @@
  public:
   explicit HandleScope(Isolate* isolate);
   ~HandleScope();
 
  private:
   VMHandles::HandlesBlock* saved_handle_block_;  // Handle block at prev scope.
   uword saved_handle_slot_;  // Next available handle slot at previous scope.
 #if defined(DEBUG)
   HandleScope* link_;  // Link to previous scope.
 #endif
-  DISALLOW_COPY_AND_ASSIGN(HandleScope);
+  DISALLOW_IMPLICIT_CONSTRUCTORS(HandleScope);
 };
 
 // Macro to start a new Handle scope.
 #define HANDLESCOPE(isolate)                                                  \
     dart::HandleScope vm_internal_handles_scope_(isolate);
 
 
 // The class NoHandleScope is used in critical regions of the virtual machine
 // code where raw dart object pointers are directly manipulated.
 // This class asserts that we do not add code that will allocate new handles
 // during this critical area.
 // It is used as follows:
 // {
 //   NOHANDLESCOPE(isolate);
 //   ....
 //   .....
 //   critical code that manipulates dart objects directly.
 //   ....
 // }
 #if defined(DEBUG)
 class NoHandleScope : public StackResource {
  public:
   explicit NoHandleScope(Isolate* isolate);
   ~NoHandleScope();
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(NoHandleScope);
+  DISALLOW_IMPLICIT_CONSTRUCTORS(NoHandleScope);
 };
 #else  // defined(DEBUG)
 class NoHandleScope : public ValueObject {
  public:
   explicit NoHandleScope(Isolate* isolate) { }
   ~NoHandleScope() { }
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(NoHandleScope);
+  DISALLOW_IMPLICIT_CONSTRUCTORS(NoHandleScope);
 };
 #endif  // defined(DEBUG)
 
 // Macro to start a no handles scope in the code.
 #define NOHANDLESCOPE(isolate)                                                \
     dart::NoHandleScope no_vm_internal_handles_scope_(isolate);
 
 }  // namespace dart
 
 #endif  // VM_HANDLES_H_