Delete unused chrome://fallback-icon/ handling

components/favicon_base/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.
 
 static_library("favicon_base") {
   sources = [
     "fallback_icon_style.cc",
     "fallback_icon_style.h",
-    "fallback_icon_url_parser.cc",
-    "fallback_icon_url_parser.h",
     "favicon_callback.h",
     "favicon_types.cc",
     "favicon_types.h",
     "favicon_url_parser.cc",
     "favicon_url_parser.h",
     "favicon_usage_data.cc",
     "favicon_usage_data.h",
     "favicon_util.cc",
     "favicon_util.h",
     "large_icon_url_parser.cc",
@@ skipping 12 matching lines @@
     "//url",
   ]
   public_deps = [
     "//skia",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
-    "fallback_icon_url_parser_unittest.cc",
     "favicon_url_parser_unittest.cc",
     "large_icon_url_parser_unittest.cc",
     "select_favicon_frames_unittest.cc",
   ]
 
   deps = [
     ":favicon_base",
     "//testing/gtest",
     "//ui/base",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//url",
   ]
 }