Add Observatory to sky dart_controller

sky/engine/bindings/dart_io.h

Index: sky/engine/bindings/dart_io.h
diff --git a/sky/engine/tonic/dart_class_provider.cc b/sky/engine/bindings/dart_io.h
similarity index 52%
copy from sky/engine/tonic/dart_class_provider.cc
copy to sky/engine/bindings/dart_io.h
index 70ce8541f3a45e5e20e2339bef186f0fb75110ae..f8f29c941b6ccc1cf8205565eb8ace8f9ac27b99 100644
--- a/sky/engine/tonic/dart_class_provider.cc
+++ b/sky/engine/bindings/dart_io.h
@@ -2,12 +2,14 @@
 // 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"
+#ifndef SKY_ENGINE_BINDINGS_DART_IO_H_
+#define SKY_ENGINE_BINDINGS_DART_IO_H_
 
 namespace blink {
 
-DartClassProvider::~DartClassProvider() {
-}
+// Initializes the dart:io event handler.
+void BootstrapDartIo();
 
 }  // namespace blink
+
+#endif  // SKY_ENGINE_BINDINGS_DART_IO_H_