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

components/url_matcher/url_matcher.h

Index: components/url_matcher/url_matcher.h
diff --git a/components/url_matcher/url_matcher.h b/components/url_matcher/url_matcher.h
index 552f1f3aa1a68299fbcbb4efb2bcadacec7901a5..2e9afe1cacfa4ddc8403a7c6e6cdac301c25f937 100644
--- a/components/url_matcher/url_matcher.h
+++ b/components/url_matcher/url_matcher.h
@@ -253,6 +253,7 @@ class URL_MATCHER_EXPORT URLQueryElementMatcherCondition {
                                   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;