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

chrome/browser/spellchecker/misspelling.h

Index: chrome/browser/spellchecker/misspelling.h
diff --git a/chrome/browser/spellchecker/misspelling.h b/chrome/browser/spellchecker/misspelling.h
index 43b64749b4b4bb06dae6c774ceb9f56aba1bf3d0..b3650fe13b32977c45378cfcc8c481968bc9bde3 100644
--- a/chrome/browser/spellchecker/misspelling.h
+++ b/chrome/browser/spellchecker/misspelling.h
@@ -39,6 +39,7 @@ struct Misspelling {
               size_t length,
               const std::vector<base::string16>& suggestions,
               uint32_t hash);
+  Misspelling(const Misspelling& other);
   ~Misspelling();
 
   // A several-word text snippet that immediately surrounds the misspelling.