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

chrome/browser/loader/chrome_resource_dispatcher_host_delegate.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 "chrome/browser/loader/chrome_resource_dispatcher_host_delegate.h"
 
 #include <stdint.h>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 293 matching lines @@
   // A http/s scheme implies that the new tab page is remote. The local NTP is
   // served from chrome-search://. To segment out remote NTPs, use the
   // TemplateURLService to find the default search engine. Note that if the
   // default search engine does not have a remote NTP, then the local NTP will
   // be shown. As of April 2016, only Bing and Google have remote NTPs.
   if (url.SchemeIsHTTPOrHTTPS()) {
     TemplateURLService* template_url_service =
         TemplateURLServiceFactory::GetForProfile(profile);
     if (!template_url_service)
       return;
-    TemplateURL* default_provider =
+    const TemplateURL* default_provider =
         template_url_service->GetDefaultSearchProvider();
     if (!default_provider)
       return;
     if (default_provider->GetEngineType(
             template_url_service->search_terms_data()) ==
         SearchEngineType::SEARCH_ENGINE_GOOGLE) {
       if (net_error == net::OK) {
         UMA_HISTOGRAM_LONG_TIMES("Net.NTP.Google.RequestTime2.Success",
                                  request_loading_time);
       } else if (net_error == net::ERR_ABORTED) {
@@ skipping 595 matching lines @@
             &ChromeResourceDispatcherHostDelegate::OnAbortedFrameLoad,
             base::Unretained(this), url, request_loading_time));
     return;
   }
 
   std::string metric_name = (request_loading_time.InMilliseconds() < 100 ?
       "Net.ErrAborted.Fast" : "Net.ErrAborted.Slow");
   rappor::SampleDomainAndRegistryFromGURL(
       g_browser_process->rappor_service(), metric_name, url);
 }