[iOS] Define global assert_no_deps and use it to prevent regressions.

components/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/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//tools/grit/repack.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
+if (is_ios) {
+  import("//ios/build/config.gni")
+}
+
 # To add a unit test to this target, make a "unit_test" source_set in your
 # component (it's important to use a source_set instead of a static library or
 # no tests will run) and add a reference here. You can add more than one unit
 # test target if convenient.
 test("components_unittests") {
   sources = [
     "test/run_all_unittests.cc",
   ]
 
   if (is_android || is_linux || is_mac || is_win) {
@@ skipping 233 matching lines @@
     deps += [
       "//components/printing/browser",
       "//components/printing/common",
       "//components/printing/renderer",
     ]
   }
 
   if (safe_browsing_mode == 2) {
     deps += [ "//components/safe_browsing_db:unit_tests_mobile" ]
   }
+
+  if (is_ios) {
+    assert_no_deps = ios_assert_no_deps
+  }
 }
 
 repack("components_tests_pak") {
   sources = [
     "$root_gen_dir/components/components_resources.pak",
     "$root_gen_dir/components/strings/components_strings_en-US.pak",
   ]
 
   output = "$root_out_dir/components_tests_resources.pak"
   deps = [
@@ skipping 153 matching lines @@
       "//base/test:test_support_perf",
       "//components/scheduler",
       "//components/visitedlink/browser",
       "//content/test:test_support",
       "//testing/gtest",
       "//testing/perf",
       "//url",
     ]
   }
 }