Add a histogram for omnibox answer suggestion types.

components/omnibox/browser/search_suggestion_parser.cc

 // Copyright 2014 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.
 
 #include "components/omnibox/browser/search_suggestion_parser.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <utility>
 
@@ skipping 506 matching lines @@
           suggestion_detail->GetString("q", &suggest_query_params);
 
           // Extract the Answer, if provided.
           const base::DictionaryValue* answer_json = NULL;
           if (suggestion_detail->GetDictionary("ansa", &answer_json) &&
               suggestion_detail->GetString("ansb", &answer_type_str)) {
             bool answer_parsed_successfully = false;
             answer = SuggestionAnswer::ParseAnswer(answer_json);
             int answer_type = 0;
             if (answer && base::StringToInt(answer_type_str, &answer_type)) {
+              UMA_HISTOGRAM_SPARSE_SLOWLY("Omnibox.AnswerParseType",
+                                          answer_type);
               answer_parsed_successfully = true;
 
               answer->set_type(answer_type);
               answer->AddImageURLsTo(&results->answers_image_urls);
 
               std::string contents;
               base::JSONWriter::Write(*answer_json, &contents);
               answer_contents = base::UTF8ToUTF16(contents);
             } else {
               answer_type_str = base::string16();
@@ skipping 10 matching lines @@
           base::CollapseWhitespace(match_contents, false),
           match_contents_prefix, annotation, answer_contents, answer_type_str,
           std::move(answer), suggest_query_params, deletion_url,
           is_keyword_result, relevance, relevances != NULL, should_prefetch,
           trimmed_input));
     }
   }
   results->relevances_from_server = relevances != NULL;
   return true;
 }