Add a new entry to omnibox_event.proto to log specific type of contextual suggestions

components/omnibox/browser/autocomplete_match.h

Index: components/omnibox/browser/autocomplete_match.h
diff --git a/components/omnibox/browser/autocomplete_match.h b/components/omnibox/browser/autocomplete_match.h
index 9ab496c7dc665b0f6ba3e7c7b95271b882cc1e00..6729b943f3f73b1bc38af4d7be1d38704d5cdf67 100644
--- a/components/omnibox/browser/autocomplete_match.h
+++ b/components/omnibox/browser/autocomplete_match.h
@@ -367,6 +367,13 @@ struct AutocompleteMatch {
   // Type of this match.
   Type type;
 
+  // Used to identify the specific source / type for suggestions by the
+  // suggest server. The meaning of individual values is determined by the
+  // provider of each suggestion type and is different for every suggestion
+  // type. Contact service providers for more details.

[Mark P, 2017/03/31 20:50:25]

To correct my earlier suggestion, perhaps instead of the last two sentences,
say,
See |result_subtype_identifier| in omnibox.event.proto for more details.

[gcomanici, 2017/04/01 16:01:52]

Done.

[Mark P, 2017/04/01 21:08:03]

In a trivial follow-up changelist, can you please revise this to say
result_subtype_identifier as I suggested?  You mentioned result_type_identifier,
which is not the name of the field in omnibox_event.proto.

ditto other file

+  // The identifier 0 is reserved for cases where this specific type is unset.
+  int subtype_identifier;
+
   // Set with a keyword provider match if this match can show a keyword hint.
   // For example, if this is a SearchProvider match for "www.amazon.com",
   // |associated_keyword| could be a KeywordProvider match for "amazon.com".