Refactor 'dart:profiler' UserTag API

runtime/vm/raw_object.h

 // Copyright (c) 2012, 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_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 1612 matching lines @@
   RawString* label_;
 
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->label_);
   }
 
   // Isolate unique tag.
   uword tag_;
 
   friend class SnapshotReader;
+  friend class Object;
 
  public:
   uword tag() const { return tag_; }
 };
 
 // Class Id predicates.
 
 inline bool RawObject::IsErrorClassId(intptr_t index) {
   // Make sure this function is updated when new Error types are added.
   ASSERT(kApiErrorCid == kErrorCid + 1 &&
@@ skipping 191 matching lines @@
   // Make sure this is updated when new TypedData types are added.
   ASSERT(kTypedDataInt8ArrayViewCid == kTypedDataInt8ArrayCid + 14);
   ASSERT(kExternalTypedDataInt8ArrayCid == kTypedDataInt8ArrayViewCid + 15);
   ASSERT(kNullCid == kExternalTypedDataInt8ArrayCid + 14);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_