Wholesale move sky/engine/tonic to tonic

tonic/dart_string.h

+// 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.
+
+#ifndef SKY_ENGINE_TONIC_DART_STRING_H_
+#define SKY_ENGINE_TONIC_DART_STRING_H_
+
+#include "base/logging.h"
+#include "dart/runtime/include/dart_api.h"
+#include "sky/engine/wtf/text/WTFString.h"
+
+namespace blink {
+
+Dart_Handle CreateDartString(StringImpl* string_impl);
+String ExternalizeDartString(Dart_Handle handle);
+
+}  // namespace blink
+
+#endif  // SKY_ENGINE_TONIC_DART_STRING_H_