[iOS] ios/web no longer depends on content::BrowserThread.

ios/web/test/test_web_thread_bundle_adapter.cc

-// 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.
-
-#include "ios/web/public/test/test_web_thread_bundle.h"
-
-#include "content/public/test/test_browser_thread_bundle.h"
-
-namespace web {
-
-namespace {
-
-int TestBrowserThreadBundleOptionsFromTestWebThreadBundleOptions(int options) {
-  int result = 0;
-  if (options & TestWebThreadBundle::IO_MAINLOOP)
-    result |= content::TestBrowserThreadBundle::IO_MAINLOOP;
-  if (options & TestWebThreadBundle::REAL_DB_THREAD)
-    result |= content::TestBrowserThreadBundle::REAL_DB_THREAD;
-  if (options & TestWebThreadBundle::REAL_FILE_THREAD)
-    result |= content::TestBrowserThreadBundle::REAL_FILE_THREAD;
-  if (options & TestWebThreadBundle::REAL_FILE_USER_BLOCKING_THREAD)
-    result |= content::TestBrowserThreadBundle::REAL_FILE_USER_BLOCKING_THREAD;
-  if (options & TestWebThreadBundle::REAL_CACHE_THREAD)
-    result |= content::TestBrowserThreadBundle::REAL_CACHE_THREAD;
-  if (options & TestWebThreadBundle::REAL_IO_THREAD)
-    result |= content::TestBrowserThreadBundle::REAL_IO_THREAD;
-  return result;
-}
-
-}  // namespace
-
-class TestWebThreadBundleImpl {
- public:
-  explicit TestWebThreadBundleImpl(int options)
-      : test_browser_thread_bundle_(
-            TestBrowserThreadBundleOptionsFromTestWebThreadBundleOptions(
-                options)) {}
-
- private:
-  content::TestBrowserThreadBundle test_browser_thread_bundle_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestWebThreadBundleImpl);
-};
-
-TestWebThreadBundle::TestWebThreadBundle()
-    : impl_(new TestWebThreadBundleImpl(DEFAULT)) {
-}
-
-TestWebThreadBundle::TestWebThreadBundle(int options)
-    : impl_(new TestWebThreadBundleImpl(options)) {
-}
-
-TestWebThreadBundle::~TestWebThreadBundle() {
-}
-
-}  // namespace web