components: Add out-of-line copy ctors for complex classes.

components/url_matcher/url_matcher.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_URL_MATCHER_URL_MATCHER_H_
 #define COMPONENTS_URL_MATCHER_URL_MATCHER_H_
 
 #include <stddef.h>
 
 #include <set>
@@ skipping 235 matching lines @@
   // Used to indicate if the query parameter is of type &key=value&
   // (ELEMENT_TYPE_KEY_VALUE) or simply &key& (ELEMENT_TYPE_KEY).
   enum QueryElementType { ELEMENT_TYPE_KEY_VALUE, ELEMENT_TYPE_KEY };
 
   URLQueryElementMatcherCondition(const std::string& key,
                                   const std::string& value,
                                   QueryValueMatchType query_value_match_type,
                                   QueryElementType query_element_type,
                                   Type match_type,
                                   URLMatcherConditionFactory* factory);
+  URLQueryElementMatcherCondition(const URLQueryElementMatcherCondition& other);

[jochen (gone - plz use gerrit), 2016/02/24 08:10:49]

i wonder whether this class should rather be DISALLOW_COPY_AND_ASSIGN. Is it
really safe to copy the string_pattern_ pointer?

[vmpstr, 2016/02/25 00:20:38]

It's being copied over here:
https://code.google.com/p/chromium/codesearch#chromium/src/components/policy/...

I think this could be a move, but unfortunately since we have an explicit dtor,
it's preventing an implicit move ctor... I already filed crbug.com/589662 for
this.

As it stands now, this patch isn't introducing new copies it's just making
things explicit where they used to be implicit. However, I do agree that this
line can be interpreted as "copies are OK to make". 

Even with a default move ctor added, there's a compilation error here:
https://code.google.com/p/chromium/codesearch#chromium/src/components/url_mat...

since that does do a copy instead of a move. 

   ~URLQueryElementMatcherCondition();
 
   bool operator<(const URLQueryElementMatcherCondition& rhs) const;
 
   // Returns whether the URL query satisfies the key value constraint.
   bool IsMatch(const std::string& canonical_url_query) const;
 
   const StringPattern* string_pattern() const { return string_pattern_; }
 
  private:
@@ skipping 158 matching lines @@
   RegexSetMatcher origin_and_path_regex_set_matcher_;
   std::set<const StringPattern*> registered_full_url_patterns_;
   std::set<const StringPattern*> registered_url_component_patterns_;
 
   DISALLOW_COPY_AND_ASSIGN(URLMatcher);
 };
 
 }  // namespace url_matcher
 
 #endif  // COMPONENTS_URL_MATCHER_URL_MATCHER_H_