Pref service: Add initial support for pref registration.

services/preferences/pref_service_factory_unittest.cc

 // Copyright (c) 2017 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 "services/preferences/public/cpp/pref_service_factory.h"
 
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/test/sequenced_worker_pool_owner.h"
@@ skipping 145 matching lines @@
   base::ScopedTempDir profile_dir_;
   std::unique_ptr<base::SequencedWorkerPoolOwner> worker_pool_owner_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefServiceFactoryTest);
 };
 
 // Check that a single client can set and read back values.
 TEST_F(PrefServiceFactoryTest, Basic) {
   auto pref_service = Create();
 
-  // TODO(tibell): Once we have a default store check the value prior to
-  // setting.
+  EXPECT_EQ(kInitialValue, pref_service->GetInteger(kKey));
   pref_service->SetInteger(kKey, kUpdatedValue);
   EXPECT_EQ(kUpdatedValue, pref_service->GetInteger(kKey));
 }
 
 // Check that updates in one client eventually propagates to the other.
 TEST_F(PrefServiceFactoryTest, MultipleClients) {
   auto pref_service = Create();
   auto pref_service2 = Create();
 
-  // TODO(tibell): Once we have a default store check the value prior to
-  // setting.
+  EXPECT_EQ(kInitialValue, pref_service->GetInteger(kKey));
+  EXPECT_EQ(kInitialValue, pref_service2->GetInteger(kKey));
   pref_service->SetInteger(kKey, kUpdatedValue);
   WaitForPrefChange(pref_service2.get(), kKey);
   EXPECT_EQ(kUpdatedValue, pref_service2->GetInteger(kKey));
 }
 
 }  // namespace
 }  // namespace prefs