Moving last generic Prefs implementation files to base/prefs/.

This completes componentization of Prefs, although there are some
remaining TODOs that were created during componentization and
interface improvement that still need to be tackled.

TBR=ben@chromium.org
BUG=155525


Review URL: https://chromiumcodereview.appspot.com/12253004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182485 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 797 insertions, 2 deletions

diff --git a/base/prefs/pref_notifier_impl_unittest.cc b/base/prefs/pref_notifier_impl_unittest.cc
new file mode 100644
index 0000000..ff36ca8
--- /dev/null
+++ b/base/prefs/pref_notifier_impl_unittest.cc
@@ -0,0 +1,227 @@
+// Copyright (c) 2011 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 "base/bind.h"
+#include "base/callback.h"
+#include "base/prefs/mock_pref_change_callback.h"
+#include "base/prefs/pref_notifier_impl.h"
+#include "base/prefs/pref_observer.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#include "base/prefs/pref_value_store.h"
+#include "base/prefs/testing_pref_service.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::_;
+using testing::Field;
+using testing::Invoke;
+using testing::Mock;
+using testing::Truly;
+
+namespace {
+
+const char kChangedPref[] = "changed_pref";
+const char kUnchangedPref[] = "unchanged_pref";
+
+class MockPrefInitObserver {
+ public:
+  MOCK_METHOD1(OnInitializationCompleted, void(bool));
+};
+
+// This is an unmodified PrefNotifierImpl, except we make
+// OnPreferenceChanged public for tests.
+class TestingPrefNotifierImpl : public PrefNotifierImpl {
+ public:
+  explicit TestingPrefNotifierImpl(PrefService* service)
+      : PrefNotifierImpl(service) {
+  }
+
+  // Make public for tests.
+  using PrefNotifierImpl::OnPreferenceChanged;
+};
+
+// Mock PrefNotifier that allows tracking of observers and notifications.
+class MockPrefNotifier : public PrefNotifierImpl {
+ public:
+  explicit MockPrefNotifier(PrefService* pref_service)
+      : PrefNotifierImpl(pref_service) {}
+  virtual ~MockPrefNotifier() {}
+
+  MOCK_METHOD1(FireObservers, void(const std::string& path));
+
+  size_t CountObserver(const char* path, PrefObserver* obs) {
+    PrefObserverMap::const_iterator observer_iterator =
+        pref_observers()->find(path);
+    if (observer_iterator == pref_observers()->end())
+      return false;
+
+    PrefObserverList* observer_list = observer_iterator->second;
+    PrefObserverList::Iterator it(*observer_list);
+    PrefObserver* existing_obs;
+    size_t count = 0;
+    while ((existing_obs = it.GetNext()) != NULL) {
+      if (existing_obs == obs)
+        count++;
+    }
+
+    return count;
+  }
+
+  // Make public for tests below.
+  using PrefNotifierImpl::OnPreferenceChanged;
+  using PrefNotifierImpl::OnInitializationCompleted;
+};
+
+class PrefObserverMock : public PrefObserver {
+ public:
+  PrefObserverMock() {}
+  virtual ~PrefObserverMock() {}
+
+  MOCK_METHOD2(OnPreferenceChanged, void(PrefServiceBase*, const std::string&));
+
+  void Expect(PrefServiceBase* prefs,
+              const std::string& pref_name,
+              const Value* value) {
+    EXPECT_CALL(*this, OnPreferenceChanged(prefs, pref_name))
+        .With(PrefValueMatches(prefs, pref_name, value));
+  }
+};
+
+// Test fixture class.
+class PrefNotifierTest : public testing::Test {
+ protected:
+  virtual void SetUp() {
+    pref_service_.registry()->RegisterBooleanPref(kChangedPref, true);
+    pref_service_.registry()->RegisterBooleanPref(kUnchangedPref, true);
+  }
+
+  TestingPrefServiceSimple pref_service_;
+
+  PrefObserverMock obs1_;
+  PrefObserverMock obs2_;
+};
+
+TEST_F(PrefNotifierTest, OnPreferenceChanged) {
+  MockPrefNotifier notifier(&pref_service_);
+  EXPECT_CALL(notifier, FireObservers(kChangedPref)).Times(1);
+  notifier.OnPreferenceChanged(kChangedPref);
+}
+
+TEST_F(PrefNotifierTest, OnInitializationCompleted) {
+  MockPrefNotifier notifier(&pref_service_);
+  MockPrefInitObserver observer;
+  notifier.AddInitObserver(
+      base::Bind(&MockPrefInitObserver::OnInitializationCompleted,
+                 base::Unretained(&observer)));
+  EXPECT_CALL(observer, OnInitializationCompleted(true));
+  notifier.OnInitializationCompleted(true);
+}
+
+TEST_F(PrefNotifierTest, AddAndRemovePrefObservers) {
+  const char pref_name[] = "homepage";
+  const char pref_name2[] = "proxy";
+
+  MockPrefNotifier notifier(&pref_service_);
+  notifier.AddPrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Re-adding the same observer for the same pref doesn't change anything.
+  // Skip this in debug mode, since it hits a DCHECK and death tests aren't
+  // thread-safe.
+#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
+  notifier.AddPrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+#endif
+
+  // Ensure that we can add the same observer to a different pref.
+  notifier.AddPrefObserver(pref_name2, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Ensure that we can add another observer to the same pref.
+  notifier.AddPrefObserver(pref_name, &obs2_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Ensure that we can remove all observers, and that removing a non-existent
+  // observer is harmless.
+  notifier.RemovePrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name, &obs2_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name2, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+}
+
+TEST_F(PrefNotifierTest, FireObservers) {
+  TestingPrefNotifierImpl notifier(&pref_service_);
+  notifier.AddPrefObserver(kChangedPref, &obs1_);
+  notifier.AddPrefObserver(kUnchangedPref, &obs1_);
+
+  EXPECT_CALL(obs1_, OnPreferenceChanged(&pref_service_, kChangedPref));
+  EXPECT_CALL(obs2_, OnPreferenceChanged(_, _)).Times(0);
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  notifier.AddPrefObserver(kChangedPref, &obs2_);
+  notifier.AddPrefObserver(kUnchangedPref, &obs2_);
+
+  EXPECT_CALL(obs1_, OnPreferenceChanged(&pref_service_, kChangedPref));
+  EXPECT_CALL(obs2_, OnPreferenceChanged(&pref_service_, kChangedPref));
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  // Make sure removing an observer from one pref doesn't affect anything else.
+  notifier.RemovePrefObserver(kChangedPref, &obs1_);
+
+  EXPECT_CALL(obs1_, OnPreferenceChanged(_, _)).Times(0);
+  EXPECT_CALL(obs2_, OnPreferenceChanged(&pref_service_, kChangedPref));
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  // Make sure removing an observer entirely doesn't affect anything else.
+  notifier.RemovePrefObserver(kUnchangedPref, &obs1_);
+
+  EXPECT_CALL(obs1_, OnPreferenceChanged(_, _)).Times(0);
+  EXPECT_CALL(obs2_, OnPreferenceChanged(&pref_service_, kChangedPref));
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  notifier.RemovePrefObserver(kChangedPref, &obs2_);
+  notifier.RemovePrefObserver(kUnchangedPref, &obs2_);
+}
+
+}  // namespace
diff --git a/base/prefs/pref_service_unittest.cc b/base/prefs/pref_service_unittest.cc
new file mode 100644
index 0000000..0c61a8e
--- /dev/null
+++ b/base/prefs/pref_service_unittest.cc
@@ -0,0 +1,316 @@
+// Copyright (c) 2012 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 <string>
+
+#include "base/prefs/json_pref_store.h"
+#include "base/prefs/mock_pref_change_callback.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_value_store.h"
+#include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/testing_pref_service.h"
+#include "base/prefs/testing_pref_store.h"
+#include "base/values.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::_;
+using testing::Mock;
+
+const char kPrefName[] = "pref.name";
+
+TEST(PrefServiceTest, NoObserverFire) {
+  TestingPrefServiceSimple prefs;
+
+  const char pref_name[] = "homepage";
+  prefs.registry()->RegisterStringPref(pref_name, std::string());
+
+  const char new_pref_value[] = "http://www.google.com/";
+  MockPrefChangeCallback obs(&prefs);
+  PrefChangeRegistrar registrar;
+  registrar.Init(&prefs);
+  registrar.Add(pref_name, obs.GetCallback());
+
+  // This should fire the checks in MockPrefChangeCallback::OnPreferenceChanged.
+  const StringValue expected_value(new_pref_value);
+  obs.Expect(pref_name, &expected_value);
+  prefs.SetString(pref_name, new_pref_value);
+  Mock::VerifyAndClearExpectations(&obs);
+
+  // Setting the pref to the same value should not set the pref value a second
+  // time.
+  EXPECT_CALL(obs, OnPreferenceChanged(_)).Times(0);
+  prefs.SetString(pref_name, new_pref_value);
+  Mock::VerifyAndClearExpectations(&obs);
+
+  // Clearing the pref should cause the pref to fire.
+  const StringValue expected_default_value("");
+  obs.Expect(pref_name, &expected_default_value);
+  prefs.ClearPref(pref_name);
+  Mock::VerifyAndClearExpectations(&obs);
+
+  // Clearing the pref again should not cause the pref to fire.
+  EXPECT_CALL(obs, OnPreferenceChanged(_)).Times(0);
+  prefs.ClearPref(pref_name);
+  Mock::VerifyAndClearExpectations(&obs);
+}
+
+TEST(PrefServiceTest, HasPrefPath) {
+  TestingPrefServiceSimple prefs;
+
+  const char path[] = "fake.path";
+
+  // Shouldn't initially have a path.
+  EXPECT_FALSE(prefs.HasPrefPath(path));
+
+  // Register the path. This doesn't set a value, so the path still shouldn't
+  // exist.
+  prefs.registry()->RegisterStringPref(path, std::string());
+  EXPECT_FALSE(prefs.HasPrefPath(path));
+
+  // Set a value and make sure we have a path.
+  prefs.SetString(path, "blah");
+  EXPECT_TRUE(prefs.HasPrefPath(path));
+}
+
+TEST(PrefServiceTest, Observers) {
+  const char pref_name[] = "homepage";
+
+  TestingPrefServiceSimple prefs;
+  prefs.SetUserPref(pref_name, Value::CreateStringValue("http://www.cnn.com"));
+  prefs.registry()->RegisterStringPref(pref_name, std::string());
+
+  const char new_pref_value[] = "http://www.google.com/";
+  const StringValue expected_new_pref_value(new_pref_value);
+  MockPrefChangeCallback obs(&prefs);
+  PrefChangeRegistrar registrar;
+  registrar.Init(&prefs);
+  registrar.Add(pref_name, obs.GetCallback());
+
+  PrefChangeRegistrar registrar_two;
+  registrar_two.Init(&prefs);
+
+  // This should fire the checks in MockPrefChangeCallback::OnPreferenceChanged.
+  obs.Expect(pref_name, &expected_new_pref_value);
+  prefs.SetString(pref_name, new_pref_value);
+  Mock::VerifyAndClearExpectations(&obs);
+
+  // Now try adding a second pref observer.
+  const char new_pref_value2[] = "http://www.youtube.com/";
+  const StringValue expected_new_pref_value2(new_pref_value2);
+  MockPrefChangeCallback obs2(&prefs);
+  obs.Expect(pref_name, &expected_new_pref_value2);
+  obs2.Expect(pref_name, &expected_new_pref_value2);
+  registrar_two.Add(pref_name, obs2.GetCallback());
+  // This should fire the checks in obs and obs2.
+  prefs.SetString(pref_name, new_pref_value2);
+  Mock::VerifyAndClearExpectations(&obs);
+  Mock::VerifyAndClearExpectations(&obs2);
+
+  // Set a recommended value.
+  const StringValue recommended_pref_value("http://www.gmail.com/");
+  obs.Expect(pref_name, &expected_new_pref_value2);
+  obs2.Expect(pref_name, &expected_new_pref_value2);
+  // This should fire the checks in obs and obs2 but with an unchanged value
+  // as the recommended value is being overridden by the user-set value.
+  prefs.SetRecommendedPref(pref_name, recommended_pref_value.DeepCopy());
+  Mock::VerifyAndClearExpectations(&obs);
+  Mock::VerifyAndClearExpectations(&obs2);
+
+  // Make sure obs2 still works after removing obs.
+  registrar.Remove(pref_name);
+  EXPECT_CALL(obs, OnPreferenceChanged(_)).Times(0);
+  obs2.Expect(pref_name, &expected_new_pref_value);
+  // This should only fire the observer in obs2.
+  prefs.SetString(pref_name, new_pref_value);
+  Mock::VerifyAndClearExpectations(&obs);
+  Mock::VerifyAndClearExpectations(&obs2);
+}
+
+// Make sure that if a preference changes type, so the wrong type is stored in
+// the user pref file, it uses the correct fallback value instead.
+TEST(PrefServiceTest, GetValueChangedType) {
+  const int kTestValue = 10;
+  TestingPrefServiceSimple prefs;
+  prefs.registry()->RegisterIntegerPref(kPrefName, kTestValue);
+
+  // Check falling back to a recommended value.
+  prefs.SetUserPref(kPrefName, Value::CreateStringValue("not an integer"));
+  const PrefService::Preference* pref = prefs.FindPreference(kPrefName);
+  ASSERT_TRUE(pref);
+  const Value* value = pref->GetValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  int actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kTestValue, actual_int_value);
+}
+
+TEST(PrefServiceTest, GetValueAndGetRecommendedValue) {
+  const int kDefaultValue = 5;
+  const int kUserValue = 10;
+  const int kRecommendedValue = 15;
+  TestingPrefServiceSimple prefs;
+  prefs.registry()->RegisterIntegerPref(kPrefName, kDefaultValue);
+
+  // Create pref with a default value only.
+  const PrefService::Preference* pref = prefs.FindPreference(kPrefName);
+  ASSERT_TRUE(pref);
+
+  // Check that GetValue() returns the default value.
+  const Value* value = pref->GetValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  int actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kDefaultValue, actual_int_value);
+
+  // Check that GetRecommendedValue() returns no value.
+  value = pref->GetRecommendedValue();
+  ASSERT_FALSE(value);
+
+  // Set a user-set value.
+  prefs.SetUserPref(kPrefName, Value::CreateIntegerValue(kUserValue));
+
+  // Check that GetValue() returns the user-set value.
+  value = pref->GetValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kUserValue, actual_int_value);
+
+  // Check that GetRecommendedValue() returns no value.
+  value = pref->GetRecommendedValue();
+  ASSERT_FALSE(value);
+
+  // Set a recommended value.
+  prefs.SetRecommendedPref(kPrefName,
+                           Value::CreateIntegerValue(kRecommendedValue));
+
+  // Check that GetValue() returns the user-set value.
+  value = pref->GetValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kUserValue, actual_int_value);
+
+  // Check that GetRecommendedValue() returns the recommended value.
+  value = pref->GetRecommendedValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kRecommendedValue, actual_int_value);
+
+  // Remove the user-set value.
+  prefs.RemoveUserPref(kPrefName);
+
+  // Check that GetValue() returns the recommended value.
+  value = pref->GetValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kRecommendedValue, actual_int_value);
+
+  // Check that GetRecommendedValue() returns the recommended value.
+  value = pref->GetRecommendedValue();
+  ASSERT_TRUE(value);
+  EXPECT_EQ(Value::TYPE_INTEGER, value->GetType());
+  actual_int_value = -1;
+  EXPECT_TRUE(value->GetAsInteger(&actual_int_value));
+  EXPECT_EQ(kRecommendedValue, actual_int_value);
+}
+
+class PrefServiceSetValueTest : public testing::Test {
+ protected:
+  static const char kName[];
+  static const char kValue[];
+
+  PrefServiceSetValueTest() : observer_(&prefs_) {}
+
+  TestingPrefServiceSimple prefs_;
+  MockPrefChangeCallback observer_;
+};
+
+const char PrefServiceSetValueTest::kName[] = "name";
+const char PrefServiceSetValueTest::kValue[] = "value";
+
+TEST_F(PrefServiceSetValueTest, SetStringValue) {
+  const char default_string[] = "default";
+  const StringValue default_value(default_string);
+  prefs_.registry()->RegisterStringPref(kName, default_string);
+
+  PrefChangeRegistrar registrar;
+  registrar.Init(&prefs_);
+  registrar.Add(kName, observer_.GetCallback());
+
+  // Changing the controlling store from default to user triggers notification.
+  observer_.Expect(kName, &default_value);
+  prefs_.Set(kName, default_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  EXPECT_CALL(observer_, OnPreferenceChanged(_)).Times(0);
+  prefs_.Set(kName, default_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  StringValue new_value(kValue);
+  observer_.Expect(kName, &new_value);
+  prefs_.Set(kName, new_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+}
+
+TEST_F(PrefServiceSetValueTest, SetDictionaryValue) {
+  prefs_.registry()->RegisterDictionaryPref(kName);
+  PrefChangeRegistrar registrar;
+  registrar.Init(&prefs_);
+  registrar.Add(kName, observer_.GetCallback());
+
+  EXPECT_CALL(observer_, OnPreferenceChanged(_)).Times(0);
+  prefs_.RemoveUserPref(kName);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  DictionaryValue new_value;
+  new_value.SetString(kName, kValue);
+  observer_.Expect(kName, &new_value);
+  prefs_.Set(kName, new_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  EXPECT_CALL(observer_, OnPreferenceChanged(_)).Times(0);
+  prefs_.Set(kName, new_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  DictionaryValue empty;
+  observer_.Expect(kName, &empty);
+  prefs_.Set(kName, empty);
+  Mock::VerifyAndClearExpectations(&observer_);
+}
+
+TEST_F(PrefServiceSetValueTest, SetListValue) {
+  prefs_.registry()->RegisterListPref(kName);
+  PrefChangeRegistrar registrar;
+  registrar.Init(&prefs_);
+  registrar.Add(kName, observer_.GetCallback());
+
+  EXPECT_CALL(observer_, OnPreferenceChanged(_)).Times(0);
+  prefs_.RemoveUserPref(kName);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  ListValue new_value;
+  new_value.Append(Value::CreateStringValue(kValue));
+  observer_.Expect(kName, &new_value);
+  prefs_.Set(kName, new_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  EXPECT_CALL(observer_, OnPreferenceChanged(_)).Times(0);
+  prefs_.Set(kName, new_value);
+  Mock::VerifyAndClearExpectations(&observer_);
+
+  ListValue empty;
+  observer_.Expect(kName, &empty);
+  prefs_.Set(kName, empty);
+  Mock::VerifyAndClearExpectations(&observer_);
+}
diff --git a/base/prefs/public/pref_change_registrar_unittest.cc b/base/prefs/public/pref_change_registrar_unittest.cc
index 5e1ad5f..b29f43a 100644
--- a/base/prefs/public/pref_change_registrar_unittest.cc
+++ b/base/prefs/public/pref_change_registrar_unittest.cc
@@ -7,7 +7,7 @@
 #include "base/prefs/pref_observer.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/public/pref_change_registrar.h"
-#include "chrome/test/base/testing_pref_service.h"
+#include "base/prefs/testing_pref_service.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
diff --git a/base/prefs/public/pref_member_unittest.cc b/base/prefs/public/pref_member_unittest.cc
index 5f1c3f1..2a68059 100644
--- a/base/prefs/public/pref_member_unittest.cc
+++ b/base/prefs/public/pref_member_unittest.cc
@@ -7,9 +7,9 @@
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/testing_pref_service.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
-#include "chrome/test/base/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
diff --git a/base/prefs/testing_pref_service.cc b/base/prefs/testing_pref_service.cc
new file mode 100644
index 0000000..22755da
--- /dev/null
+++ b/base/prefs/testing_pref_service.cc
@@ -0,0 +1,56 @@
+// Copyright (c) 2012 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 "base/prefs/testing_pref_service.h"
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/prefs/default_pref_store.h"
+#include "base/prefs/pref_notifier_impl.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_value_store.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+template<>
+TestingPrefServiceBase<PrefService, PrefRegistry>::TestingPrefServiceBase(
+    TestingPrefStore* managed_prefs,
+    TestingPrefStore* user_prefs,
+    TestingPrefStore* recommended_prefs,
+    PrefRegistry* pref_registry,
+    PrefNotifierImpl* pref_notifier)
+    : PrefService(pref_notifier,
+                  new PrefValueStore(
+                      managed_prefs,
+                      NULL,
+                      NULL,
+                      user_prefs,
+                      recommended_prefs,
+                      pref_registry->defaults(),
+                      pref_notifier),
+                  user_prefs,
+                  pref_registry,
+                  base::Bind(
+                      &TestingPrefServiceBase<
+                          PrefService, PrefRegistry>::HandleReadError),
+                  false),
+      managed_prefs_(managed_prefs),
+      user_prefs_(user_prefs),
+      recommended_prefs_(recommended_prefs) {
+}
+
+TestingPrefServiceSimple::TestingPrefServiceSimple()
+    : TestingPrefServiceBase<PrefService, PrefRegistry>(
+        new TestingPrefStore(),
+        new TestingPrefStore(),
+        new TestingPrefStore(),
+        new PrefRegistrySimple(),
+        new PrefNotifierImpl()) {
+}
+
+TestingPrefServiceSimple::~TestingPrefServiceSimple() {
+}
+
+PrefRegistrySimple* TestingPrefServiceSimple::registry() {
+  return static_cast<PrefRegistrySimple*>(DeprecatedGetPrefRegistry());
+}
diff --git a/base/prefs/testing_pref_service.h b/base/prefs/testing_pref_service.h
new file mode 100644
index 0000000..9d290fe
--- /dev/null
+++ b/base/prefs/testing_pref_service.h
@@ -0,0 +1,196 @@
+// Copyright (c) 2012 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.
+
+#ifndef BASE_PREFS_TESTING_PREF_SERVICE_H_
+#define BASE_PREFS_TESTING_PREF_SERVICE_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/prefs/pref_registry.h"
+#include "base/prefs/pref_service.h"
+#include "base/prefs/testing_pref_store.h"
+
+class PrefNotifierImpl;
+class PrefRegistrySimple;
+class TestingPrefStore;
+
+// A PrefService subclass for testing. It operates totally in memory and
+// provides additional API for manipulating preferences at the different levels
+// (managed, extension, user) conveniently.
+//
+// Use this via its specializations, e.g. TestingPrefServiceSimple.
+template <class SuperPrefService, class ConstructionPrefRegistry>
+class TestingPrefServiceBase : public SuperPrefService {
+ public:
+  virtual ~TestingPrefServiceBase();
+
+  // Read the value of a preference from the managed layer. Returns NULL if the
+  // preference is not defined at the managed layer.
+  const Value* GetManagedPref(const char* path) const;
+
+  // Set a preference on the managed layer and fire observers if the preference
+  // changed. Assumes ownership of |value|.
+  void SetManagedPref(const char* path, Value* value);
+
+  // Clear the preference on the managed layer and fire observers if the
+  // preference has been defined previously.
+  void RemoveManagedPref(const char* path);
+
+  // Similar to the above, but for user preferences.
+  const Value* GetUserPref(const char* path) const;
+  void SetUserPref(const char* path, Value* value);
+  void RemoveUserPref(const char* path);
+
+  // Similar to the above, but for recommended policy preferences.
+  const Value* GetRecommendedPref(const char* path) const;
+  void SetRecommendedPref(const char* path, Value* value);
+  void RemoveRecommendedPref(const char* path);
+
+  // Do-nothing implementation for TestingPrefService.
+  static void HandleReadError(PersistentPrefStore::PrefReadError error) {}
+
+ protected:
+  TestingPrefServiceBase(
+      TestingPrefStore* managed_prefs,
+      TestingPrefStore* user_prefs,
+      TestingPrefStore* recommended_prefs,
+      ConstructionPrefRegistry* pref_registry,
+      PrefNotifierImpl* pref_notifier);
+
+ private:
+  // Reads the value of the preference indicated by |path| from |pref_store|.
+  // Returns NULL if the preference was not found.
+  const Value* GetPref(TestingPrefStore* pref_store, const char* path) const;
+
+  // Sets the value for |path| in |pref_store|.
+  void SetPref(TestingPrefStore* pref_store, const char* path, Value* value);
+
+  // Removes the preference identified by |path| from |pref_store|.
+  void RemovePref(TestingPrefStore* pref_store, const char* path);
+
+  // Pointers to the pref stores our value store uses.
+  scoped_refptr<TestingPrefStore> managed_prefs_;
+  scoped_refptr<TestingPrefStore> user_prefs_;
+  scoped_refptr<TestingPrefStore> recommended_prefs_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestingPrefServiceBase);
+};
+
+// Test version of PrefService.
+class TestingPrefServiceSimple
+    : public TestingPrefServiceBase<PrefService, PrefRegistry> {
+ public:
+  TestingPrefServiceSimple();
+  virtual ~TestingPrefServiceSimple();
+
+  // This is provided as a convenience for registering preferences on
+  // an existing TestingPrefServiceSimple instance. On a production
+  // PrefService you would do all registrations before constructing
+  // it, passing it a PrefRegistry via its constructor (or via
+  // e.g. PrefServiceBuilder).
+  PrefRegistrySimple* registry();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestingPrefServiceSimple);
+};
+
+template<>
+TestingPrefServiceBase<PrefService, PrefRegistry>::TestingPrefServiceBase(
+    TestingPrefStore* managed_prefs,
+    TestingPrefStore* user_prefs,
+    TestingPrefStore* recommended_prefs,
+    PrefRegistry* pref_registry,
+    PrefNotifierImpl* pref_notifier);
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::~TestingPrefServiceBase() {
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+const Value* TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::GetManagedPref(
+        const char* path) const {
+  return GetPref(managed_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::SetManagedPref(
+        const char* path, Value* value) {
+  SetPref(managed_prefs_, path, value);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::RemoveManagedPref(
+        const char* path) {
+  RemovePref(managed_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+const Value* TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::GetUserPref(
+        const char* path) const {
+  return GetPref(user_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::SetUserPref(
+        const char* path, Value* value) {
+  SetPref(user_prefs_, path, value);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::RemoveUserPref(
+        const char* path) {
+  RemovePref(user_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+const Value* TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::GetRecommendedPref(
+        const char* path) const {
+  return GetPref(recommended_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::SetRecommendedPref(
+        const char* path, Value* value) {
+  SetPref(recommended_prefs_, path, value);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::RemoveRecommendedPref(
+        const char* path) {
+  RemovePref(recommended_prefs_, path);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+const Value* TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::GetPref(
+        TestingPrefStore* pref_store, const char* path) const {
+  const Value* res;
+  return pref_store->GetValue(path, &res) ? res : NULL;
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::SetPref(
+        TestingPrefStore* pref_store, const char* path, Value* value) {
+  pref_store->SetValue(path, value);
+}
+
+template<class SuperPrefService, class ConstructionPrefRegistry>
+void TestingPrefServiceBase<
+    SuperPrefService, ConstructionPrefRegistry>::RemovePref(
+        TestingPrefStore* pref_store, const char* path) {
+  pref_store->RemoveValue(path);
+}
+
+#endif  // BASE_PREFS_TESTING_PREF_SERVICE_H_