Delete unused chrome://fallback-icon/ handling

chrome/browser/favicon/fallback_icon_service_factory.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_FALLBACK_ICON_SERVICE_FACTORY_H_
-#define CHROME_BROWSER_FAVICON_FALLBACK_ICON_SERVICE_FACTORY_H_
-
-#include "base/macros.h"
-#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
-
-namespace base {
-template <typename T> struct DefaultSingletonTraits;
-}
-
-namespace content {
-class BrowserContext;
-}
-
-namespace favicon {
-class FallbackIconService;
-}
-
-// Singleton that owns all FallbackIconService and associates them with
-// BrowserContext instances.
-class FallbackIconServiceFactory : public BrowserContextKeyedServiceFactory {
- public:
-  static favicon::FallbackIconService* GetForBrowserContext(
-      content::BrowserContext* context);
-
-  static FallbackIconServiceFactory* GetInstance();
-
- private:
-  friend struct base::DefaultSingletonTraits<FallbackIconServiceFactory>;
-
-  FallbackIconServiceFactory();
-  ~FallbackIconServiceFactory() override;
-
-  // BrowserContextKeyedServiceFactory:
-  content::BrowserContext* GetBrowserContextToUse(
-      content::BrowserContext* context) const override;
-  KeyedService* BuildServiceInstanceFor(
-      content::BrowserContext* context) const override;
-  bool ServiceIsNULLWhileTesting() const override;
-
-  DISALLOW_COPY_AND_ASSIGN(FallbackIconServiceFactory);
-};
-
-#endif  // CHROME_BROWSER_FAVICON_FALLBACK_ICON_SERVICE_FACTORY_H_