Add persistent handles to service protocol and Observatory UI

runtime/bin/stdio_patch.dart

Index: runtime/bin/stdio_patch.dart
diff --git a/runtime/bin/stdio_patch.dart b/runtime/bin/stdio_patch.dart
index fbc308346bc28d00aa3867101c5820fbf0b701f6..7e66009655ce1c76856d4b56dc08751de6c8cc29 100644
--- a/runtime/bin/stdio_patch.dart
+++ b/runtime/bin/stdio_patch.dart
@@ -32,7 +32,7 @@ patch class _StdIOUtils {
   static int _socketType(nativeSocket) {
     var result = _getSocketType(nativeSocket);
     if (result is OSError) {
-      throw new FileSystemException("Error retreiving socket type", "", result);
+      throw new FileSystemException("Error retrieving socket type", "", result);
     }
     return result;
   }