Split up ios/web:test_support.

ios/chrome/browser/signin/BUILD.gn

 # Copyright 2016 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("signin") {
   sources = [
     "about_signin_internals_factory.cc",
     "about_signin_internals_factory.h",
     "account_consistency_service_factory.h",
     "account_consistency_service_factory.mm",
@@ skipping 110 matching lines @@
     "//google_apis",
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state:test_support",
     "//ios/chrome/browser/prefs:browser_prefs",
     "//ios/chrome/browser/sync",
     "//ios/chrome/browser/sync:test_support",
     "//ios/chrome/test:test_support",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser/signin",
     "//ios/public/provider/chrome/browser/signin:test_support",
-    "//ios/web:test_support",
+    "//ios/web/public/test:test_support",
+    "//ios/web/public/test/fakes:test_support",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/ocmock",
   ]
 }
 
 source_set("signin_internal") {
   sources = [
     "signin_capability.cc",
     "signin_capability.h",
   ]
   deps = [
     ":signin",
     "//base",
     "//components/signin/core/browser",
     "//ios/chrome/browser/browser_state",
   ]
 }