Dart: Reorganize files

mojo/dart/unittests/embedder_tester/dart_test.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 MOJO_DART_EMBEDDER_TEST_DART_TEST_H_
-#define MOJO_DART_EMBEDDER_TEST_DART_TEST_H_
+#ifndef MOJO_DART_UNITTESTS_EMBEDDER_TESTER_DART_TEST_H_
+#define MOJO_DART_UNITTESTS_EMBEDDER_TESTER_DART_TEST_H_
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "base/rand_util.h"
 #include "mojo/dart/embedder/dart_controller.h"
 #include "mojo/public/c/system/types.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 30 matching lines @@
                                 int64_t count) {
     EXPECT_TRUE(Dart_IsError(error));
     *exception = true;
     *closed_handles = count;
   }
 };
 
 }  // namespace dart
 }  // namespace mojo
 
-#endif  // MOJO_DART_EMBEDDER_TEST_DART_TEST_H_
+#endif  // MOJO_DART_UNITTESTS_EMBEDDER_TESTER_DART_TEST_H_