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

components/search_engines/template_url_service.cc

Index: components/search_engines/template_url_service.cc
diff --git a/components/search_engines/template_url_service.cc b/components/search_engines/template_url_service.cc
index dfce55d0938808463ee41f3312197384c0f83c05..9433205bea41da61a676ca39c2822d552e7ae555 100644
--- a/components/search_engines/template_url_service.cc
+++ b/components/search_engines/template_url_service.cc
@@ -614,11 +614,6 @@ void TemplateURLService::SetUserSelectedDefaultSearchProvider(
   }
 }
 
-TemplateURL* TemplateURLService::GetDefaultSearchProvider() {
-  return const_cast<TemplateURL*>(
-      static_cast<const TemplateURLService*>(this)->GetDefaultSearchProvider());
-}
-
 const TemplateURL* TemplateURLService::GetDefaultSearchProvider() const {
   return loaded_ ? default_search_provider_
                  : initial_default_search_provider_.get();