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

chrome/BUILD.gn

Index: chrome/BUILD.gn
diff --git a/chrome/BUILD.gn b/chrome/BUILD.gn
index a4f5e2cdbf98273fb0d87e57f2298fa75a515d29..c12de85edf504d17e548f4c329ea0315699bc231 100644
--- a/chrome/BUILD.gn
+++ b/chrome/BUILD.gn
@@ -36,6 +36,8 @@ if (is_android) {
   import("//third_party/icu/config.gni")
 }
 
+assert(!is_ios, "Chromium/iOS shouldn't use anything in //chrome")
+
 if (enable_resource_whitelist_generation) {
   chrome_resource_whitelist = "$target_gen_dir/chrome_resource_whitelist.txt"
 }
@@ -1415,7 +1417,7 @@ group("extra_resources") {
     "//chrome/browser/resources:webapks_ui_resources",
   ]
 
-  if (!is_android && !is_ios) {
+  if (!is_android) {
     public_deps += [
       "//chrome/browser/resources:component_extension_resources",
       "//chrome/browser/resources:options_resources",