Remove non-const version of GetDefaultSearchProvider() and make all callers call the const version

components/omnibox/browser/history_url_provider.cc

 // Copyright (c) 2012 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/history_url_provider.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 401 matching lines @@
     // different port and/or path) before.
     url_row_ = history::URLRow(url);
     type_ = UNVISITED_INTRANET;
   }
 }
 
 HistoryURLProviderParams::HistoryURLProviderParams(
     const AutocompleteInput& input,
     bool trim_http,
     const AutocompleteMatch& what_you_typed_match,
-    TemplateURL* default_search_provider,
+    const TemplateURL* default_search_provider,
     const SearchTermsData& search_terms_data)
     : origin_task_runner(base::SequencedTaskRunnerHandle::Get()),
       input(input),
       prevent_inline_autocomplete(input.prevent_inline_autocomplete()),
       trim_http(trim_http),
       what_you_typed_match(what_you_typed_match),
       failed(false),
       exact_suggestion_is_in_history(false),
       promote_type(NEITHER),
       default_search_provider(
@@ skipping 64 matching lines @@
   // We'll need the history service to run both passes, so try to obtain it.
   history::HistoryService* const history_service =
       client()->GetHistoryService();
   if (!history_service)
     return;
 
   // Get the default search provider and search terms data now since we have to
   // retrieve these on the UI thread, and the second pass runs on the history
   // thread. |template_url_service| can be null when testing.
   TemplateURLService* template_url_service = client()->GetTemplateURLService();
-  TemplateURL* default_search_provider = template_url_service ?
+  const TemplateURL* default_search_provider = template_url_service ?
       template_url_service->GetDefaultSearchProvider() : nullptr;
 
   // Create the data structure for the autocomplete passes.  We'll save this off
   // onto the |params_| member for later deletion below if we need to run pass
   // 2.
   std::unique_ptr<HistoryURLProviderParams> params(new HistoryURLProviderParams(
       fixed_up_input, trim_http, what_you_typed_match, default_search_provider,
       client()->GetSearchTermsData()));
   // Note that we use the non-fixed-up input here, since fixup may strip
   // trailing whitespace.
@@ skipping 669 matching lines @@
     AutocompleteMatch::ClassifyLocationInString(base::string16::npos, 0,
         match.contents.length(), ACMatchClassification::URL,
         &match.contents_class);
   }
   match.description = info.title();
   match.description_class =
       ClassifyDescription(params.input.text(), match.description);
   RecordAdditionalInfoFromUrlRow(info, &match);
   return match;
 }