Refactor wait_util so it isn't coupled to EarlGrey.

ios/web/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.
 
 import("//ios/build/config.gni")
 import("//ios/web/js_compile.gni")
 import("//testing/test.gni")
 import("//tools/grit/grit_rule.gni")
 
 source_set("web_arc") {
@@ skipping 314 matching lines @@
 }
 
 source_set("earl_grey_test_support") {
   testonly = true
 
   deps = [
     ":test_support",
     ":web",
     "//base",
     "//base/test:test_support",
+    "//ios/testing:ios_test_support",
     "//ios/testing/earl_grey:earl_grey_support",
     "//ios/third_party/earl_grey",
   ]
 
   sources = [
     "public/test/earl_grey/js_test_util.h",
     "public/test/earl_grey/js_test_util.mm",
     "public/test/earl_grey/web_view_actions.h",
     "public/test/earl_grey/web_view_actions.mm",
     "public/test/earl_grey/web_view_matchers.h",
@@ skipping 262 matching lines @@
 }
 
 grit("resources") {
   source = "ios_web_resources.grd"
   use_qualified_include = true
   outputs = [
     "grit/ios_web_resources.h",
     "ios_web_resources.pak",
   ]
 }