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

components/omnibox/browser/history_url_provider.h

 // 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.
 
 #ifndef COMPONENTS_OMNIBOX_BROWSER_HISTORY_URL_PROVIDER_H_
 #define COMPONENTS_OMNIBOX_BROWSER_HISTORY_URL_PROVIDER_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 86 matching lines @@
   // See comments on |promote_type| below.
   enum PromoteType {
     WHAT_YOU_TYPED_MATCH,
     FRONT_HISTORY_MATCH,
     NEITHER,
   };
 
   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);
   ~HistoryURLProviderParams();
 
   const scoped_refptr<base::SequencedTaskRunner> origin_task_runner;
 
   // A copy of the autocomplete input. We need the copy since this object will
   // live beyond the original query while it runs on the history thread.
   AutocompleteInput input;
 
   // Should inline autocompletion be disabled? This is initalized from
@@ skipping 225 matching lines @@
 
   // Params controlling experimental behavior of this provider.
   HUPScoringParams scoring_params_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryURLProvider);
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_HISTORY_URL_PROVIDER_H_