gn: Fix clang plugin on ios.

build/config/clang/BUILD.gn

 # Copyright (c) 2013 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.
 
 declare_args() {
   # Indicates if the build should use the Chrome-specific plugins for enforcing
   # coding guidelines, etc.
   clang_use_chrome_plugins = true
 }
 
 config("find_bad_constructs") {
   if (clang_use_chrome_plugins) {
     cflags = [
       "-Xclang", "-load",
       "-Xclang",
     ]
 
-    if (is_mac) {
+    if (is_mac || is_ios) {
       cflags += [ rebase_path(
         "//third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib",
         ".", root_build_dir) ]
     } else if (is_linux) {
       cflags += [ rebase_path(
         "//third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so",
         ".", root_build_dir) ]
     }
 
     cflags += [
       "-Xclang", "-add-plugin",
       "-Xclang", "find-bad-constructs",
     ]
   }
 }