autocomplete: Add AutocompleteMatch::MergeClassifications()

chrome/browser/autocomplete/autocomplete_match.h

Index: chrome/browser/autocomplete/autocomplete_match.h
diff --git a/chrome/browser/autocomplete/autocomplete_match.h b/chrome/browser/autocomplete/autocomplete_match.h
index 3296ac4d326537e4e3418016594bfac128ec5a1d..ca324581c0536586009f5c24ae0b1fd44b73e637 100644
--- a/chrome/browser/autocomplete/autocomplete_match.h
+++ b/chrome/browser/autocomplete/autocomplete_match.h
@@ -144,6 +144,12 @@ struct AutocompleteMatch {
                                        int style,
                                        ACMatchClassifications* classifications);
 
+  // Returns a new vector of classifications containing the merged contents of
+  // |classifications1| and |classifications2|.
+  static ACMatchClassifications MergeClassifications(
+      const ACMatchClassifications& classifications1,
+      const ACMatchClassifications& classifications2);
+
   // Converts classifications to and from a serialized string representation
   // (using comma-separated integers to sequentially list positions and styles).
   static std::string ClassificationsToString(