Fix components/rlz/BUILD.gn on iOS.

components/rlz/BUILD.gn

 # Copyright 2015 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.
 
 source_set("rlz") {
   sources = [
     "rlz_tracker.cc",
     "rlz_tracker.h",
     "rlz_tracker_chromeos.cc",
     "rlz_tracker_delegate.h",
     "rlz_tracker_ios.cc",
     "rlz_tracker_mac.cc",
     "rlz_tracker_win.cc",
   ]
 
   deps = [
     "//base",
     "//components/google/core/browser",
     "//net",
     "//rlz:rlz_lib",
   ]
 
   if (is_ios) {
-    deps = [
-      "//ui/base",
-    ]
+    deps += [ "//ui/base" ]
   }
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "rlz_tracker_unittest.cc",
   ]
 
   deps = [
     "//net:test_support",
     "//rlz:test_support",
     "//ui/base",
     ":rlz",
   ]
 }