Issue 6279 - Make HashContainer movable and optimize resizing by moving entries.

compiled/StringMap.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 75 matching lines @@
   };
 
   template<typename Key, typename Value>
   struct StringMapEntry : StringSetEntry<Key>
   {
     typedef StringSetEntry<Key> super;
     typedef Value value_type;
 
     value_type second;
 
+    StringMapEntry& operator=(const StringMapEntry&) = default;
+    StringMapEntry& operator=(StringMapEntry&&) = default;
+
     StringMapEntry(typename super::key_type_cref key = Key(),
                    value_type value = value_type())
-        : super(key), second(value)
+       : super(key), second(std::move(value))
     {
     }
 
     void erase()
     {
       super::erase();
       second = value_type();
     }
   };
 }
 
 using StringSet = Set<StringMap_internal::StringSetEntry<DependentString>>;
 
 template<typename Value>
 using StringMap = Map<StringMap_internal::StringMapEntry<DependentString, Value>>;
 template<typename Value>
 using OwnedStringMap = Map<StringMap_internal::StringMapEntry<OwnedString, Value>>;