Don't check is_ios in chrome/, it's always false there.

chrome/browser/resources/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("//chrome/common/features.gni")
 import("//tools/grit/grit_rule.gni")
 
+assert(!is_ios, "Chromium/iOS shouldn't use anything in //chrome")
+
 grit("net_internals_resources") {
   source = "net_internals_resources.grd"
   defines = chrome_grit_defines
   outputs = [
     "grit/net_internals_resources.h",
     "net_internals_resources.pak",
   ]
   output_dir = "$root_gen_dir/chrome"
 }
 
@@ skipping 42 matching lines @@
 grit("translate_internals_resources") {
   source = "translate_internals_resources.grd"
   defines = chrome_grit_defines
   outputs = [
     "grit/translate_internals_resources.h",
     "translate_internals_resources.pak",
   ]
   output_dir = "$root_gen_dir/chrome"
 }
 
-if (!is_ios && !is_android) {
+if (!is_android) {
   grit("component_extension_resources") {
     source = "component_extension_resources.grd"
     defines = chrome_grit_defines
     if (enable_hangout_services_extension) {
       defines += [ "enable_hangout_services_extension" ]
     }
 
     outputs = [
       "grit/component_extension_resources.h",
       "grit/component_extension_resources_map.cc",
@@ skipping 41 matching lines @@
     source = "options_test_resources.grd"
     defines = chrome_grit_defines
     outputs = [
       "grit/options_test_resources.h",
       "options_test_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
   }
 }
 
-if (!is_ios) {
-  grit("quota_internals_resources") {
-    source = "quota_internals_resources.grd"
-    defines = chrome_grit_defines
-    outputs = [
-      "grit/quota_internals_resources.h",
-      "quota_internals_resources.pak",
-    ]
-    output_dir = "$root_gen_dir/chrome"
-  }
+grit("quota_internals_resources") {
+  source = "quota_internals_resources.grd"
+  defines = chrome_grit_defines
+  outputs = [
+    "grit/quota_internals_resources.h",
+    "quota_internals_resources.pak",
+  ]
+  output_dir = "$root_gen_dir/chrome"
+}
 
-  grit("webapks_ui_resources") {
-    source = "webapks_ui_resources.grd"
-    defines = chrome_grit_defines
-    outputs = [
-      "grit/webapks_ui_resources.h",
-      "webapks_ui_resources.pak",
-    ]
-    output_dir = "$root_gen_dir/chrome"
-  }
+grit("webapks_ui_resources") {
+  source = "webapks_ui_resources.grd"
+  defines = chrome_grit_defines
+  outputs = [
+    "grit/webapks_ui_resources.h",
+    "webapks_ui_resources.pak",
+  ]
+  output_dir = "$root_gen_dir/chrome"
 }
 
 if (enable_extensions) {
   grit("sync_file_system_internals_resources") {
     source = "sync_file_system_internals_resources.grd"
     defines = chrome_grit_defines
     outputs = [
       "grit/sync_file_system_internals_resources.h",
       "sync_file_system_internals_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
   }
 }