[AiS] Add a new AutocompleteMatchType for Answers in Suggest.

chrome/browser/autocomplete/base_search_provider.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 "chrome/browser/autocomplete/base_search_provider.h"
 
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/icu_string_conversions.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/json/json_writer.h"
@@ skipping 897 matching lines @@
           suggestion_detail->GetString("mp", &match_contents_prefix);
           // Error correction for bad data from server.
           if (match_contents.empty())
             match_contents = suggestion;
           suggestion_detail->GetString("a", &annotation);
           suggestion_detail->GetString("q", &suggest_query_params);
 
           // Extract Answers, if provided.
           const base::DictionaryValue* answer_json = NULL;
           if (suggestion_detail->GetDictionary("ansa", &answer_json)) {
+            match_type = AutocompleteMatchType::SEARCH_SUGGEST_ANSWER;

[Peter Kasting, 2014/06/10 21:49:46]

My only concern here would be if there's a validation issue, where if we don't
get "correct" data from the ansa/ansb parameters (or whatever), some later stage
will auto-downgrade this match to appear like a normal search result or
something.  If that could ever happen, we should ensure it happens here so we
tag the match type correctly for what the user will actually see.

[Justin Donnelly, 2014/06/11 15:51:53]

Good question, but no we don't plan to downgrade answers.  If the JSON is
missing required data or malformed, we're going to drop the answer altogether. 
(The current frontend code does, in fact downgrade but my next CL is going to
change this.)

             std::string contents;
             base::JSONWriter::Write(answer_json, &contents);
             answer_contents = base::UTF8ToUTF16(contents);
             suggestion_detail->GetString("ansb", &answer_type);
           }
         }
       }
 
       bool should_prefetch = static_cast<int>(index) == prefetch_index;
       // TODO(kochi): Improve calculator suggestion presentation.
@@ skipping 40 matching lines @@
 }
 
 void BaseSearchProvider::OnDeletionComplete(
     bool success, SuggestionDeletionHandler* handler) {
   RecordDeletionResult(success);
   SuggestionDeletionHandlers::iterator it = std::find(
       deletion_handlers_.begin(), deletion_handlers_.end(), handler);
   DCHECK(it != deletion_handlers_.end());
   deletion_handlers_.erase(it);
 }