Move implementation of dart:mojo.internal to mojo/public/platform/dart

mojo/public/platform/dart/mojo_natives.h

Index: mojo/public/platform/dart/mojo_natives.h
diff --git a/mojo/dart/embedder/mojo_natives.h b/mojo/public/platform/dart/mojo_natives.h
similarity index 77%
rename from mojo/dart/embedder/mojo_natives.h
rename to mojo/public/platform/dart/mojo_natives.h
index 3ae635d6c11fb48e901c7869bcafa12fde16d1ad..596c140fc21d22d3b5d846dbf55576df761edcfa 100644
--- a/mojo/dart/embedder/mojo_natives.h
+++ b/mojo/public/platform/dart/mojo_natives.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef MOJO_DART_EMBEDDER_MOJO_NATIVES_H_
-#define MOJO_DART_EMBEDDER_MOJO_NATIVES_H_
+#ifndef MOJO_PUBLIC_PLATFORM_DART_MOJO_NATIVES_H_
+#define MOJO_PUBLIC_PLATFORM_DART_MOJO_NATIVES_H_
 
 #include "dart/runtime/include/dart_api.h"
 
@@ -19,4 +19,4 @@ const uint8_t* MojoNativeSymbol(Dart_NativeFunction nf);
 }  // namespace dart
 }  // namespace mojo
 
-#endif  // MOJO_DART_EMBEDDER_MOJO_NATIVES_H_
+#endif  // MOJO_PUBLIC_PLATFORM_DART_MOJO_NATIVES_H_