components: Cleanup class/struct fwd declarations

components/translate/core/browser/translate_ranker.h

 // Copyright 2016 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_TRANSLATE_CORE_BROWSER_TRANSLATE_RANKER_H_
 #define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_RANKER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/feature_list.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/singleton.h"
 
 namespace chrome_intelligence {
 class TranslateRankerModel;
 }
 
 namespace metrics {
 class TranslateEventProto;
 }
 
 namespace translate {
 
 class TranslatePrefs;
-class TranslateRankerMetricsProvider;
 class TranslateURLFetcher;
 
 // Features used to enable ranker query, enforcement and logging. Note that
 // enabling enforcement implies (forces) enabling queries.
 extern const base::Feature kTranslateRankerQuery;
 extern const base::Feature kTranslateRankerEnforcement;
 extern const base::Feature kTranslateRankerLogging;
 
 // If enabled, downloads a translate ranker model and uses it to determine
 // whether the user should be given a translation prompt or not.
@@ skipping 83 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(TranslateRankerTest, CalculateScore);
 
   friend struct base::DefaultSingletonTraits<TranslateRanker>;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateRanker);
 };
 
 }  // namespace translate
 
 #endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_RANKER_H_