Update to nan 2.0
diff --git a/src/node/ext/completion_queue_async_worker.cc b/src/node/ext/completion_queue_async_worker.cc
index bf2cd94..3a79f7c 100644
--- a/src/node/ext/completion_queue_async_worker.cc
+++ b/src/node/ext/completion_queue_async_worker.cc
@@ -46,9 +46,8 @@
 const int max_queue_threads = 2;
 
 using v8::Function;
-using v8::Handle;
+using v8::Local;
 using v8::Object;
-using v8::Persistent;
 using v8::Value;
 
 grpc_completion_queue *CompletionQueueAsyncWorker::queue;
@@ -57,7 +56,7 @@
 int CompletionQueueAsyncWorker::waiting_next_calls;
 
 CompletionQueueAsyncWorker::CompletionQueueAsyncWorker()
-    : NanAsyncWorker(NULL) {}
+    : Nan::AsyncWorker(NULL) {}
 
 CompletionQueueAsyncWorker::~CompletionQueueAsyncWorker() {}
 
@@ -72,42 +71,42 @@
 grpc_completion_queue *CompletionQueueAsyncWorker::GetQueue() { return queue; }
 
 void CompletionQueueAsyncWorker::Next() {
-  NanScope();
+  Nan::HandleScope scope;
   if (current_threads < max_queue_threads) {
     CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
-    NanAsyncQueueWorker(worker);
+    Nan::AsyncQueueWorker(worker);
   } else {
     waiting_next_calls += 1;
   }
 }
 
-void CompletionQueueAsyncWorker::Init(Handle<Object> exports) {
-  NanScope();
+void CompletionQueueAsyncWorker::Init(Local<Object> exports) {
+  Nan::HandleScope scope;
   current_threads = 0;
   waiting_next_calls = 0;
   queue = grpc_completion_queue_create(NULL);
 }
 
 void CompletionQueueAsyncWorker::HandleOKCallback() {
-  NanScope();
+  Nan::HandleScope scope;
   if (waiting_next_calls > 0) {
     waiting_next_calls -= 1;
     CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
-    NanAsyncQueueWorker(worker);
+    Nan::AsyncQueueWorker(worker);
   } else {
     current_threads -= 1;
   }
-  NanCallback *callback = GetTagCallback(result.tag);
-  Handle<Value> argv[] = {NanNull(), GetTagNodeValue(result.tag)};
+  Nan::Callback *callback = GetTagCallback(result.tag);
+  Local<Value> argv[] = {Nan::Null(), GetTagNodeValue(result.tag)};
   callback->Call(2, argv);
 
   DestroyTag(result.tag);
 }
 
 void CompletionQueueAsyncWorker::HandleErrorCallback() {
-  NanScope();
-  NanCallback *callback = GetTagCallback(result.tag);
-  Handle<Value> argv[] = {NanError(ErrorMessage())};
+  Nan::HandleScope scope;
+  Nan::Callback *callback = GetTagCallback(result.tag);
+  Local<Value> argv[] = {Nan::Error(ErrorMessage())};
 
   callback->Call(1, argv);