Delete unused chrome://fallback-icon/ handling

chrome/browser/favicon/chrome_fallback_icon_client_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_CHROME_FALLBACK_ICON_CLIENT_FACTORY_H_
-#define CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_FACTORY_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 FallbackIconClient;
-}
-
-// Singleton that owns all ChromeFallbackIconClients and associates them with
-// Profiles.
-class ChromeFallbackIconClientFactory
-    : public BrowserContextKeyedServiceFactory {
- public:
-  // Returns the instance of FallbackIconClient associated with this profile
-  // (creating one if none exists).
-  static favicon::FallbackIconClient* GetForBrowserContext(
-      content::BrowserContext* context);
-
-  // Returns an instance of the factory singleton.
-  static ChromeFallbackIconClientFactory* GetInstance();
-
- private:
-  friend struct base::DefaultSingletonTraits<ChromeFallbackIconClientFactory>;
-
-  ChromeFallbackIconClientFactory();
-  ~ChromeFallbackIconClientFactory() override;
-
-  // BrowserContextKeyedServiceFactory:
-  KeyedService* BuildServiceInstanceFor(
-      content::BrowserContext* context) const override;
-};
-
-#endif  // CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_FACTORY_H_