Make header include guards great again

runtime/vm/tags.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#ifndef VM_TAGS_H_
-#define VM_TAGS_H_
+#ifndef RUNTIME_VM_TAGS_H_
+#define RUNTIME_VM_TAGS_H_
 
 #include "vm/allocation.h"
 
 namespace dart {
 
 class Isolate;
 class JSONObject;
 class RuntimeEntry;
 
 #define VM_TAG_LIST(V)                                                         \
@@ skipping 99 matching lines @@
   static const char* TagName(uword tag_id);
   static bool IsUserTag(uword tag_id) {
     return (tag_id >= kUserTagIdOffset) &&
            (tag_id < kUserTagIdOffset + kMaxUserTags);
   }
 };
 
 
 }  // namespace dart
 
-#endif  // VM_TAGS_H_
+#endif  // RUNTIME_VM_TAGS_H_