Delete unused chrome://fallback-icon/ handling

chrome/browser/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 383 matching lines @@
     "engagement/site_engagement_service_factory.h",
     "experiments/memory_ablation_experiment.cc",
     "experiments/memory_ablation_experiment.h",
 
     # Oh hey, all the cool browser/extensions files are hanging out in
     # //chrome/browser/extensions/BUILD.gn
     "external_protocol/external_protocol_handler.cc",
     "external_protocol/external_protocol_handler.h",
     "external_protocol/external_protocol_observer.cc",
     "external_protocol/external_protocol_observer.h",
-    "favicon/chrome_fallback_icon_client.cc",
-    "favicon/chrome_fallback_icon_client.h",
-    "favicon/chrome_fallback_icon_client_factory.cc",
-    "favicon/chrome_fallback_icon_client_factory.h",
     "favicon/chrome_favicon_client.cc",
     "favicon/chrome_favicon_client.h",
-    "favicon/fallback_icon_service_factory.cc",
-    "favicon/fallback_icon_service_factory.h",
     "favicon/favicon_service_factory.cc",
     "favicon/favicon_service_factory.h",
     "favicon/favicon_utils.cc",
     "favicon/favicon_utils.h",
     "favicon/large_icon_service_factory.cc",
     "favicon/large_icon_service_factory.h",
     "file_select_helper.cc",
     "file_select_helper.h",
     "file_select_helper_mac.mm",
     "flag_descriptions.cc",
@@ skipping 4347 matching lines @@
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }
 
 service_manifest("preferences_forwarder_manifest") {
   name = "preferences_forwarder"
   source = "prefs/forwarder_manifest.json"
 }