Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/dictionary_hash_store_contents.cc

Index: components/user_prefs/tracked/dictionary_hash_store_contents.cc
diff --git a/components/user_prefs/tracked/dictionary_hash_store_contents.cc b/components/user_prefs/tracked/dictionary_hash_store_contents.cc
index 6bddb6591f86cec3d9e97067f057225829391275..288c1bf45dba68226b4261c44a6e0a5c5079b164 100644
--- a/components/user_prefs/tracked/dictionary_hash_store_contents.cc
+++ b/components/user_prefs/tracked/dictionary_hash_store_contents.cc
@@ -28,6 +28,16 @@ void DictionaryHashStoreContents::RegisterProfilePrefs(
   registry->RegisterStringPref(kSuperMACPref, std::string());
 }
 
+bool DictionaryHashStoreContents::IsCopyable() const {
+  return false;
+}
+
+std::unique_ptr<HashStoreContents> DictionaryHashStoreContents::MakeCopy()
+    const {
+  NOTREACHED() << "DictionaryHashStoreContents does not support MakeCopy";
+  return nullptr;
+}
+
 base::StringPiece DictionaryHashStoreContents::GetUMASuffix() const {
   // To stay consistent with existing reported data, do not append a suffix
   // when reporting UMA stats for this content.
@@ -121,4 +131,4 @@ base::DictionaryValue* DictionaryHashStoreContents::GetMutableContents(
     storage_->Set(kPreferenceMACs, macs_dict);
   }
   return macs_dict;
-}
+}