Use 'new' in all the snapshot reallocation functions instead of realloc.

runtime/lib/isolate.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 "platform/assert.h"
+#include "platform/utils.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/longjump.h"
 #include "vm/message_handler.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
@@ skipping 14 matching lines @@
         class_name_(class_name),
         port_id_(port_id) {}
 
   char* library_url_;
   char* class_name_;
   intptr_t port_id_;
 };
 
 
 static uint8_t* allocator(uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
-  void* new_ptr = realloc(reinterpret_cast<void*>(ptr), new_size);
-  return reinterpret_cast<uint8_t*>(new_ptr);
+  return Utils::Realloc(ptr, old_size, new_size);
 }
 
 
 // TODO(turnidge): Move to DartLibraryCalls.
 static RawObject* ReceivePortCreate(intptr_t port_id) {
   Isolate* isolate = Isolate::Current();
   Function& func =
       Function::Handle(isolate,
                        isolate->object_store()->receive_port_create_function());
   const int kNumArguments = 1;
@@ skipping 243 matching lines @@
 
 DEFINE_NATIVE_ENTRY(isolate_getPortInternal, 0) {
   const Object& port = Object::Handle(ReceivePortCreate(isolate->main_port()));
   if (port.IsError()) {
     Exceptions::PropagateError(Error::Cast(port));
   }
   return port.raw();
 }
 
 }  // namespace dart