Add dart_invoke to tonic for calls into App code.

sky/engine/tonic/dart_invoke.cc

Index: sky/engine/tonic/dart_invoke.cc
diff --git a/sky/engine/tonic/dart_invoke.cc b/sky/engine/tonic/dart_invoke.cc
new file mode 100644
index 0000000000000000000000000000000000000000..92c4055d261b8d8d1cddc027cbcc4083d3a19a2c
--- /dev/null
+++ b/sky/engine/tonic/dart_invoke.cc
@@ -0,0 +1,29 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// 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_invoke.h"
+
+#include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+#include "sky/engine/tonic/dart_error.h"
+
+namespace blink {
+
+bool DartInvokeAppField(Dart_Handle target, Dart_Handle name,
+                               int number_of_arguments,
+                               Dart_Handle* arguments) {
+  TRACE_EVENT0("sky", "DartInvoke::DartInvokeAppField");
+  return LogIfError(Dart_Invoke(target, name, number_of_arguments, arguments));
+}
+
+bool DartInvokeAppClosure(Dart_Handle closure,
+                          int number_of_arguments,
+                          Dart_Handle* arguments) {
+  TRACE_EVENT0("sky", "DartInvoke::DartInvokeAppClosure");
+  return LogIfError(
+      Dart_InvokeClosure(closure, number_of_arguments, arguments));
+}
+
+}  // namespace blink