Simplify TranslateRanker API.

components/translate/core/browser/mock_translate_ranker.cc

 // Copyright 2017 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/translate/core/browser/mock_translate_ranker.h"
 
 #include "components/metrics/proto/translate_event.pb.h"
 #include "url/gurl.h"
 
 namespace translate {
 namespace testing {
 
 MockTranslateRanker::MockTranslateRanker() {}
 
 MockTranslateRanker::~MockTranslateRanker() {}
 
 uint32_t MockTranslateRanker::GetModelVersion() const {
   return model_version_;
 }
 
 bool MockTranslateRanker::ShouldOfferTranslation(
-    const TranslatePrefs& /* translate_prefs */,
-    const std::string& /* src_lang */,
-    const std::string& /* dst_lang */,
     metrics::TranslateEventProto* /*translate_event */) {
   return should_offer_translation_;
 }
 
 void MockTranslateRanker::FlushTranslateEvents(
     std::vector<metrics::TranslateEventProto>* events) {
   events->swap(event_cache_);
   event_cache_.clear();
 }
 
 }  // namespace testing
 }  // namespace translate