Delete unused chrome://fallback-icon/ handling

chrome/browser/favicon/chrome_fallback_icon_client.h

-// Copyright 2015 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 CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_H_
-#define CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_H_
-
-#include <string>
-#include <vector>
-
-#include "base/macros.h"
-#include "components/favicon/core/fallback_icon_client.h"
-
-// ChromeFallbackIconClient implements the FallbackIconClient interface.
-class ChromeFallbackIconClient : public favicon::FallbackIconClient {
- public:
-  ChromeFallbackIconClient();
-  ~ChromeFallbackIconClient() override;
-
-  // FallbackIconClient implementation:
-  const std::vector<std::string>& GetFontNameList() const override;
-
- private:
-  std::vector<std::string> font_list_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeFallbackIconClient);
-};
-
-#endif  // CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_H_