Add Observatory to sky dart_controller

sky/engine/bindings/dart_io.cc

Index: sky/engine/bindings/dart_io.cc
diff --git a/sky/engine/tonic/dart_class_provider.cc b/sky/engine/bindings/dart_io.cc
similarity index 50%
copy from sky/engine/tonic/dart_class_provider.cc
copy to sky/engine/bindings/dart_io.cc
index 70ce8541f3a45e5e20e2339bef186f0fb75110ae..df92aa42ff9306a9cd5098bf5dccf283d4ab3374 100644
--- a/sky/engine/tonic/dart_class_provider.cc
+++ b/sky/engine/bindings/dart_io.cc
@@ -2,12 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "sky/engine/config.h"
-#include "sky/engine/tonic/dart_class_provider.h"
+#include "dart_io.h"
+
+#include "bin/eventhandler.h"
+#include "bin/thread.h"
 
 namespace blink {
 
-DartClassProvider::~DartClassProvider() {
+void BootstrapDartIo() {
+  // Bootstrap 'dart:io' event handler.
+  dart::bin::Thread::InitOnce();
+  dart::bin::EventHandler::Start();
 }
 
 }  // namespace blink