Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/registry_hash_store_contents_win.h

Index: components/user_prefs/tracked/registry_hash_store_contents_win.h
diff --git a/components/user_prefs/tracked/registry_hash_store_contents_win.h b/components/user_prefs/tracked/registry_hash_store_contents_win.h
index c18245e86f0f37d7e4c44abc811a4bfc35819b8e..b44898ef69842faa32f82948456a657bc37880e3 100644
--- a/components/user_prefs/tracked/registry_hash_store_contents_win.h
+++ b/components/user_prefs/tracked/registry_hash_store_contents_win.h
@@ -18,6 +18,8 @@ class RegistryHashStoreContentsWin : public HashStoreContents {
                                         const base::string16& store_key);
 
   // HashStoreContents overrides:
+  bool IsCopyable() const override;
+  std::unique_ptr<HashStoreContents> MakeCopy() const override;
   base::StringPiece GetUMASuffix() const override;
   void Reset() override;
   bool GetMac(const std::string& path, std::string* out_value) override;
@@ -37,9 +39,11 @@ class RegistryHashStoreContentsWin : public HashStoreContents {
   void SetSuperMac(const std::string& super_mac) override;
 
  private:
-  const base::string16 preference_key_name_;
+  // Helper constructor for |MakeCopy|.
+  explicit RegistryHashStoreContentsWin(
+      const RegistryHashStoreContentsWin& other);
 
-  DISALLOW_COPY_AND_ASSIGN(RegistryHashStoreContentsWin);
+  const base::string16 preference_key_name_;
 };
 
 #endif  // COMPONENTS_USER_PREFS_TRACKED_PREF_REGISTRY_HASH_STORE_CONTENTS_H_