[iOS] Add FakeSyncService and factory for testing

ios/public/test/test_chrome_browser_provider.mm

 // Copyright 2013 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/public/test/test_chrome_browser_provider.h"
 
 #include "base/logging.h"
 #include "ios/public/test/fake_string_provider.h"
+#import "ios/public/test/test_keyed_service_provider.h"
 
 namespace {
 const char kUIScheme[] = "uischeme";
 }
 
 namespace ios {
 
 TestChromeBrowserProvider::TestChromeBrowserProvider()
-    : string_provider_(new FakeStringProvider) {
+    : string_provider_(new FakeStringProvider),
+      test_keyed_service_provider_(new TestKeyedServiceProvider) {
 }
 
 TestChromeBrowserProvider::~TestChromeBrowserProvider() {
 }
 
 // static
 TestChromeBrowserProvider* TestChromeBrowserProvider::GetTestProvider() {
   ChromeBrowserProvider* provider = GetChromeBrowserProvider();
   DCHECK(provider);
   return static_cast<TestChromeBrowserProvider*>(provider);
 }
 
 StringProvider* TestChromeBrowserProvider::GetStringProvider() {
   return string_provider_.get();
 }
 
+KeyedServiceProvider* TestChromeBrowserProvider::GetKeyedServiceProvider() {
+  return test_keyed_service_provider_.get();
+}
+
 const char* TestChromeBrowserProvider::GetChromeUIScheme() {
   return kUIScheme;
 }
 
 }  // namespace ios