Merging PrefSetObserver into PrefChangeRegistrar.

Removing Chrome-specific factories and inlining what they used to do.  One was (after the bulk of this change) just adding a single pref to the PrefChangeRegistrar, the other was used in only one place.

TBR=usageupdate@chromium.org,ben@chromium.org
BUG=155525,122215

Review URL: https://chromiumcodereview.appspot.com/11110014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162007 0039d316-1c4b-4281-b951-d872f2087c98

18 files changed, 156 insertions, 277 deletions

diff --git a/chrome/browser/api/prefs/pref_change_registrar.cc b/chrome/browser/api/prefs/pref_change_registrar.cc
index 2b05f5b..43d2b4a 100644
--- a/chrome/browser/api/prefs/pref_change_registrar.cc
+++ b/chrome/browser/api/prefs/pref_change_registrar.cc
@@ -67,3 +67,23 @@ void PrefChangeRegistrar::RemoveAll() {
 bool PrefChangeRegistrar::IsEmpty() const {
   return observers_.empty();
 }
+
+bool PrefChangeRegistrar::IsObserved(const std::string& pref) {
+  for (std::set<ObserverRegistration>::const_iterator it = observers_.begin();
+       it != observers_.end(); ++it) {
+    if (it->first == pref)
+      return true;
+  }
+  return false;
+}
+
+bool PrefChangeRegistrar::IsManaged() {
+  for (std::set<ObserverRegistration>::const_iterator it = observers_.begin();
+       it != observers_.end(); ++it) {
+    const PrefServiceBase::Preference* pref =
+        service_->FindPreference(it->first.c_str());
+    if (pref && pref->IsManaged())
+      return true;
+  }
+  return false;
+}
diff --git a/chrome/browser/api/prefs/pref_change_registrar.h b/chrome/browser/api/prefs/pref_change_registrar.h
index 6f2d296..e6e2114d 100644
--- a/chrome/browser/api/prefs/pref_change_registrar.h
+++ b/chrome/browser/api/prefs/pref_change_registrar.h
@@ -47,6 +47,12 @@ class PrefChangeRegistrar {
   // Returns true if no pref observers are registered.
   bool IsEmpty() const;
 
+  // Check whether |pref| is in the set of preferences being observed.
+  bool IsObserved(const std::string& pref);
+
+  // Check whether any of the observed preferences has the managed bit set.
+  bool IsManaged();
+
  private:
   typedef std::pair<std::string, content::NotificationObserver*>
       ObserverRegistration;
diff --git a/chrome/browser/api/prefs/pref_change_registrar_unittest.cc b/chrome/browser/api/prefs/pref_change_registrar_unittest.cc
index f9235dc..2152cce2 100644
--- a/chrome/browser/api/prefs/pref_change_registrar_unittest.cc
+++ b/chrome/browser/api/prefs/pref_change_registrar_unittest.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/test/base/testing_pref_service.h"
 #include "content/public/browser/notification_details.h"
@@ -118,3 +120,88 @@ TEST_F(PrefChangeRegistrarTest, RemoveAll) {
   // worked (rather than the registrar destructor doing the work).
   Mock::VerifyAndClearExpectations(service());
 }
+
+class ObserveSetOfPreferencesTest : public testing::Test {
+ public:
+  virtual void SetUp() {
+    pref_service_.reset(new TestingPrefService);
+    pref_service_->RegisterStringPref(prefs::kHomePage,
+                                      "http://google.com",
+                                      PrefService::UNSYNCABLE_PREF);
+    pref_service_->RegisterBooleanPref(prefs::kHomePageIsNewTabPage,
+                                       false,
+                                       PrefService::UNSYNCABLE_PREF);
+    pref_service_->RegisterStringPref(prefs::kApplicationLocale,
+                                      "",
+                                      PrefService::UNSYNCABLE_PREF);
+  }
+
+  PrefChangeRegistrar* CreatePrefChangeRegistrar(
+        content::NotificationObserver* observer) {
+    PrefChangeRegistrar* pref_set = new PrefChangeRegistrar();
+    pref_set->Init(pref_service_.get());
+    pref_set->Add(prefs::kHomePage, observer);
+    pref_set->Add(prefs::kHomePageIsNewTabPage, observer);
+    return pref_set;
+  }
+
+  scoped_ptr<TestingPrefService> pref_service_;
+};
+
+TEST_F(ObserveSetOfPreferencesTest, IsObserved) {
+  scoped_ptr<PrefChangeRegistrar> pref_set(CreatePrefChangeRegistrar(NULL));
+  EXPECT_TRUE(pref_set->IsObserved(prefs::kHomePage));
+  EXPECT_TRUE(pref_set->IsObserved(prefs::kHomePageIsNewTabPage));
+  EXPECT_FALSE(pref_set->IsObserved(prefs::kApplicationLocale));
+}
+
+TEST_F(ObserveSetOfPreferencesTest, IsManaged) {
+  scoped_ptr<PrefChangeRegistrar> pref_set(CreatePrefChangeRegistrar(NULL));
+  EXPECT_FALSE(pref_set->IsManaged());
+  pref_service_->SetManagedPref(prefs::kHomePage,
+                                Value::CreateStringValue("http://crbug.com"));
+  EXPECT_TRUE(pref_set->IsManaged());
+  pref_service_->SetManagedPref(prefs::kHomePageIsNewTabPage,
+                                Value::CreateBooleanValue(true));
+  EXPECT_TRUE(pref_set->IsManaged());
+  pref_service_->RemoveManagedPref(prefs::kHomePage);
+  EXPECT_TRUE(pref_set->IsManaged());
+  pref_service_->RemoveManagedPref(prefs::kHomePageIsNewTabPage);
+  EXPECT_FALSE(pref_set->IsManaged());
+}
+
+MATCHER_P(PrefNameDetails, name, "details references named preference") {
+  std::string* pstr =
+      reinterpret_cast<const content::Details<std::string>&>(arg).ptr();
+  return pstr && *pstr == name;
+}
+
+TEST_F(ObserveSetOfPreferencesTest, Observe) {
+  using testing::_;
+  using testing::Mock;
+
+  content::MockNotificationObserver observer;
+  scoped_ptr<PrefChangeRegistrar> pref_set(
+      CreatePrefChangeRegistrar(&observer));
+
+  EXPECT_CALL(observer,
+              Observe(int(chrome::NOTIFICATION_PREF_CHANGED),
+                      content::Source<PrefService>(pref_service_.get()),
+                      PrefNameDetails(prefs::kHomePage)));
+  pref_service_->SetUserPref(prefs::kHomePage,
+                             Value::CreateStringValue("http://crbug.com"));
+  Mock::VerifyAndClearExpectations(&observer);
+
+  EXPECT_CALL(observer,
+              Observe(int(chrome::NOTIFICATION_PREF_CHANGED),
+                      content::Source<PrefService>(pref_service_.get()),
+                      PrefNameDetails(prefs::kHomePageIsNewTabPage)));
+  pref_service_->SetUserPref(prefs::kHomePageIsNewTabPage,
+                             Value::CreateBooleanValue(true));
+  Mock::VerifyAndClearExpectations(&observer);
+
+  EXPECT_CALL(observer, Observe(_, _, _)).Times(0);
+  pref_service_->SetUserPref(prefs::kApplicationLocale,
+                             Value::CreateStringValue("en_US.utf8"));
+  Mock::VerifyAndClearExpectations(&observer);
+}
diff --git a/chrome/browser/net/pref_proxy_config_tracker_impl.cc b/chrome/browser/net/pref_proxy_config_tracker_impl.cc
index 6b4c30f..9760f02 100644
--- a/chrome/browser/net/pref_proxy_config_tracker_impl.cc
+++ b/chrome/browser/net/pref_proxy_config_tracker_impl.cc
@@ -7,7 +7,6 @@
 #include "base/bind.h"
 #include "base/values.h"
 #include "chrome/browser/prefs/pref_service.h"
-#include "chrome/browser/prefs/pref_set_observer.h"
 #include "chrome/browser/prefs/proxy_config_dictionary.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/pref_names.h"
@@ -130,8 +129,8 @@ PrefProxyConfigTrackerImpl::PrefProxyConfigTrackerImpl(
       chrome_proxy_config_service_(NULL),
       update_pending_(true) {
   config_state_ = ReadPrefConfig(&pref_config_);
-  proxy_prefs_observer_.reset(
-      PrefSetObserver::CreateProxyPrefSetObserver(pref_service_, this));
+  proxy_prefs_.Init(pref_service);
+  proxy_prefs_.Add(prefs::kProxy, this);
 }
 
 PrefProxyConfigTrackerImpl::~PrefProxyConfigTrackerImpl() {
@@ -150,7 +149,7 @@ void PrefProxyConfigTrackerImpl::SetChromeProxyConfigService(
 void PrefProxyConfigTrackerImpl::DetachFromPrefService() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   // Stop notifications.
-  proxy_prefs_observer_.reset();
+  proxy_prefs_.RemoveAll();
   pref_service_ = NULL;
   SetChromeProxyConfigService(NULL);
 }
diff --git a/chrome/browser/net/pref_proxy_config_tracker_impl.h b/chrome/browser/net/pref_proxy_config_tracker_impl.h
index c55a651..c393486 100644
--- a/chrome/browser/net/pref_proxy_config_tracker_impl.h
+++ b/chrome/browser/net/pref_proxy_config_tracker_impl.h
@@ -9,13 +9,13 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/prefs/proxy_config_dictionary.h"
 #include "content/public/browser/notification_observer.h"
 #include "net/proxy/proxy_config.h"
 #include "net/proxy/proxy_config_service.h"
 
 class PrefService;
-class PrefSetObserver;
 
 // A net::ProxyConfigService implementation that applies preference proxy
 // settings (pushed from PrefProxyConfigTrackerImpl) as overrides to the proxy
@@ -157,7 +157,7 @@ class PrefProxyConfigTrackerImpl : public content::NotificationObserver {
   PrefService* pref_service_;
   ChromeProxyConfigService* chrome_proxy_config_service_;  // Weak ptr.
   bool update_pending_;  // True if config has not been pushed to network stack.
-  scoped_ptr<PrefSetObserver> proxy_prefs_observer_;
+  PrefChangeRegistrar proxy_prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefProxyConfigTrackerImpl);
 };
diff --git a/chrome/browser/prefs/pref_set_observer.cc b/chrome/browser/prefs/pref_set_observer.cc
deleted file mode 100644
index 8694b23..0000000
--- a/chrome/browser/prefs/pref_set_observer.cc
+++ /dev/null
@@ -1,81 +0,0 @@
-// 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 "chrome/browser/prefs/pref_set_observer.h"
-
-#include "chrome/common/pref_names.h"
-#include "chrome/browser/extensions/extension_prefs.h"
-#include "content/public/browser/notification_types.h"
-
-PrefSetObserver::PrefSetObserver(PrefService* pref_service,
-                                 content::NotificationObserver* observer)
-    : pref_service_(pref_service),
-      observer_(observer) {
-  registrar_.Init(pref_service);
-}
-
-PrefSetObserver::~PrefSetObserver() {}
-
-void PrefSetObserver::AddPref(const std::string& pref) {
-  if (!prefs_.count(pref) && pref_service_->FindPreference(pref.c_str())) {
-    prefs_.insert(pref);
-    registrar_.Add(pref.c_str(), this);
-  }
-}
-
-void PrefSetObserver::RemovePref(const std::string& pref) {
-  if (prefs_.erase(pref))
-    registrar_.Remove(pref.c_str(), this);
-}
-
-bool PrefSetObserver::IsObserved(const std::string& pref) {
-  return prefs_.count(pref) > 0;
-}
-
-bool PrefSetObserver::IsManaged() {
-  for (PrefSet::const_iterator i(prefs_.begin()); i != prefs_.end(); ++i) {
-    const PrefService::Preference* pref =
-        pref_service_->FindPreference(i->c_str());
-    if (pref && pref->IsManaged())
-      return true;
-  }
-  return false;
-}
-
-// static
-PrefSetObserver* PrefSetObserver::CreateProxyPrefSetObserver(
-    PrefService* pref_service,
-    content::NotificationObserver* observer) {
-  PrefSetObserver* pref_set = new PrefSetObserver(pref_service, observer);
-  pref_set->AddPref(prefs::kProxy);
-
-  return pref_set;
-}
-
-// static
-PrefSetObserver* PrefSetObserver::CreateProtectedPrefSetObserver(
-    PrefService* pref_service,
-    content::NotificationObserver* observer) {
-  PrefSetObserver* pref_set = new PrefSetObserver(pref_service, observer);
-  // Homepage.
-  pref_set->AddPref(prefs::kHomePageIsNewTabPage);
-  pref_set->AddPref(prefs::kHomePage);
-  pref_set->AddPref(prefs::kShowHomeButton);
-  // Session startup.
-  pref_set->AddPref(prefs::kRestoreOnStartup);
-  pref_set->AddPref(prefs::kURLsToRestoreOnStartup);
-  // Pinned tabs.
-  pref_set->AddPref(prefs::kPinnedTabs);
-  // Extensions.
-  pref_set->AddPref(extensions::ExtensionPrefs::kExtensionsPref);
-
-  return pref_set;
-}
-
-void PrefSetObserver::Observe(int type,
-                              const content::NotificationSource& source,
-                              const content::NotificationDetails& details) {
-  if (observer_)
-    observer_->Observe(type, source, details);
-}
diff --git a/chrome/browser/prefs/pref_set_observer.h b/chrome/browser/prefs/pref_set_observer.h
deleted file mode 100644
index 438aaad..0000000
--- a/chrome/browser/prefs/pref_set_observer.h
+++ /dev/null
@@ -1,60 +0,0 @@
-// 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 CHROME_BROWSER_PREFS_PREF_SET_OBSERVER_H_
-#define CHROME_BROWSER_PREFS_PREF_SET_OBSERVER_H_
-
-#include <set>
-
-#include "base/basictypes.h"
-#include "chrome/browser/api/prefs/pref_change_registrar.h"
-#include "chrome/browser/prefs/pref_service.h"
-#include "content/public/browser/notification_observer.h"
-
-// Observes the state of a set of preferences and allows to query their combined
-// managed bits.
-class PrefSetObserver : public content::NotificationObserver {
- public:
-  // Initialize with an empty set of preferences.
-  PrefSetObserver(PrefService* pref_service,
-                  content::NotificationObserver* observer);
-  virtual ~PrefSetObserver();
-
-  // Add a |pref| to the set of preferences to observe.
-  void AddPref(const std::string& pref);
-  // Remove |pref| from the set of observed peferences.
-  void RemovePref(const std::string& pref);
-
-  // Check whether |pref| is in the set of observed preferences.
-  bool IsObserved(const std::string& pref);
-  // Check whether any of the observed preferences has the managed bit set.
-  bool IsManaged();
-
-  // Create a pref set observer for all preferences relevant to proxies.
-  static PrefSetObserver* CreateProxyPrefSetObserver(
-      PrefService* pref_service,
-      content::NotificationObserver* observer);
-
-  // Create a pref set observer for preferences accessed by ProtectorService.
-  static PrefSetObserver* CreateProtectedPrefSetObserver(
-      PrefService* pref_service,
-      content::NotificationObserver* observer);
-
- private:
-  // Overridden from content::NotificationObserver.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  typedef std::set<std::string> PrefSet;
-  PrefSet prefs_;
-
-  PrefService* pref_service_;
-  PrefChangeRegistrar registrar_;
-  content::NotificationObserver* observer_;
-
-  DISALLOW_COPY_AND_ASSIGN(PrefSetObserver);
-};
-
-#endif  // CHROME_BROWSER_PREFS_PREF_SET_OBSERVER_H_
diff --git a/chrome/browser/prefs/pref_set_observer_unittest.cc b/chrome/browser/prefs/pref_set_observer_unittest.cc
deleted file mode 100644
index adb6011..0000000
--- a/chrome/browser/prefs/pref_set_observer_unittest.cc
+++ /dev/null
@@ -1,98 +0,0 @@
-// 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 "chrome/browser/prefs/pref_set_observer.h"
-#include "chrome/common/chrome_notification_types.h"
-#include "chrome/common/pref_names.h"
-#include "chrome/test/base/testing_pref_service.h"
-#include "content/public/browser/notification_details.h"
-#include "content/public/browser/notification_source.h"
-#include "content/public/test/mock_notification_observer.h"
-#include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-// Unit tests for PrefSetObserver.
-class PrefSetObserverTest : public testing::Test {
- public:
-  virtual void SetUp() {
-    pref_service_.reset(new TestingPrefService);
-    pref_service_->RegisterStringPref(prefs::kHomePage,
-                                      "http://google.com",
-                                      PrefService::UNSYNCABLE_PREF);
-    pref_service_->RegisterBooleanPref(prefs::kHomePageIsNewTabPage,
-                                       false,
-                                       PrefService::UNSYNCABLE_PREF);
-    pref_service_->RegisterStringPref(prefs::kApplicationLocale,
-                                      "",
-                                      PrefService::UNSYNCABLE_PREF);
-  }
-
-  PrefSetObserver* CreatePrefSetObserver(
-        content::NotificationObserver* observer) {
-    PrefSetObserver* pref_set =
-        new PrefSetObserver(pref_service_.get(), observer);
-    pref_set->AddPref(prefs::kHomePage);
-    pref_set->AddPref(prefs::kHomePageIsNewTabPage);
-    return pref_set;
-  }
-
-  scoped_ptr<TestingPrefService> pref_service_;
-};
-
-TEST_F(PrefSetObserverTest, IsObserved) {
-  scoped_ptr<PrefSetObserver> pref_set(CreatePrefSetObserver(NULL));
-  EXPECT_TRUE(pref_set->IsObserved(prefs::kHomePage));
-  EXPECT_TRUE(pref_set->IsObserved(prefs::kHomePageIsNewTabPage));
-  EXPECT_FALSE(pref_set->IsObserved(prefs::kApplicationLocale));
-}
-
-TEST_F(PrefSetObserverTest, IsManaged) {
-  scoped_ptr<PrefSetObserver> pref_set(CreatePrefSetObserver(NULL));
-  EXPECT_FALSE(pref_set->IsManaged());
-  pref_service_->SetManagedPref(prefs::kHomePage,
-                                Value::CreateStringValue("http://crbug.com"));
-  EXPECT_TRUE(pref_set->IsManaged());
-  pref_service_->SetManagedPref(prefs::kHomePageIsNewTabPage,
-                                Value::CreateBooleanValue(true));
-  EXPECT_TRUE(pref_set->IsManaged());
-  pref_service_->RemoveManagedPref(prefs::kHomePage);
-  EXPECT_TRUE(pref_set->IsManaged());
-  pref_service_->RemoveManagedPref(prefs::kHomePageIsNewTabPage);
-  EXPECT_FALSE(pref_set->IsManaged());
-}
-
-MATCHER_P(PrefNameDetails, name, "details references named preference") {
-  std::string* pstr =
-      reinterpret_cast<const content::Details<std::string>&>(arg).ptr();
-  return pstr && *pstr == name;
-}
-
-TEST_F(PrefSetObserverTest, Observe) {
-  using testing::_;
-  using testing::Mock;
-
-  content::MockNotificationObserver observer;
-  scoped_ptr<PrefSetObserver> pref_set(CreatePrefSetObserver(&observer));
-
-  EXPECT_CALL(observer,
-              Observe(int(chrome::NOTIFICATION_PREF_CHANGED),
-                      content::Source<PrefService>(pref_service_.get()),
-                      PrefNameDetails(prefs::kHomePage)));
-  pref_service_->SetUserPref(prefs::kHomePage,
-                             Value::CreateStringValue("http://crbug.com"));
-  Mock::VerifyAndClearExpectations(&observer);
-
-  EXPECT_CALL(observer,
-              Observe(int(chrome::NOTIFICATION_PREF_CHANGED),
-                      content::Source<PrefService>(pref_service_.get()),
-                      PrefNameDetails(prefs::kHomePageIsNewTabPage)));
-  pref_service_->SetUserPref(prefs::kHomePageIsNewTabPage,
-                             Value::CreateBooleanValue(true));
-  Mock::VerifyAndClearExpectations(&observer);
-
-  EXPECT_CALL(observer, Observe(_, _, _)).Times(0);
-  pref_service_->SetUserPref(prefs::kApplicationLocale,
-                             Value::CreateStringValue("en_US.utf8"));
-  Mock::VerifyAndClearExpectations(&observer);
-}
diff --git a/chrome/browser/protector/base_prefs_change.cc b/chrome/browser/protector/base_prefs_change.cc
index 7e9dca6..2a4a871 100644
--- a/chrome/browser/protector/base_prefs_change.cc
+++ b/chrome/browser/protector/base_prefs_change.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/prefs/pref_set_observer.h"
+#include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/protector/base_prefs_change.h"
 #include "chrome/browser/protector/protected_prefs_watcher.h"
@@ -23,7 +23,7 @@ BasePrefsChange::~BasePrefsChange() {
 bool BasePrefsChange::Init(Profile* profile) {
   if (!BaseSettingChange::Init(profile))
     return false;
-  pref_observer_.reset(new PrefSetObserver(profile->GetPrefs(), this));
+  pref_observer_.Init(profile->GetPrefs());
   return true;
 }
 
@@ -35,12 +35,12 @@ void BasePrefsChange::InitWhenDisabled(Profile* profile) {
 }
 
 void BasePrefsChange::DismissOnPrefChange(const std::string& pref_name) {
-  DCHECK(!pref_observer_->IsObserved(pref_name));
-  pref_observer_->AddPref(pref_name);
+  DCHECK(!pref_observer_.IsObserved(pref_name));
+  pref_observer_.Add(pref_name.c_str(), this);
 }
 
 void BasePrefsChange::IgnorePrefChanges() {
-  pref_observer_.reset();
+  pref_observer_.RemoveAll();
 }
 
 void BasePrefsChange::Observe(int type,
@@ -48,7 +48,7 @@ void BasePrefsChange::Observe(int type,
                              const content::NotificationDetails& details) {
   DCHECK(type == chrome::NOTIFICATION_PREF_CHANGED);
   const std::string* pref_name = content::Details<std::string>(details).ptr();
-  DCHECK(pref_name && pref_observer_->IsObserved(*pref_name));
+  DCHECK(pref_name && pref_observer_.IsObserved(*pref_name));
   // Will delete this instance.
   ProtectorServiceFactory::GetForProfile(profile())->DismissChange(this);
 }
diff --git a/chrome/browser/protector/base_prefs_change.h b/chrome/browser/protector/base_prefs_change.h
index 96ed5ce..a3f6b86 100644
--- a/chrome/browser/protector/base_prefs_change.h
+++ b/chrome/browser/protector/base_prefs_change.h
@@ -8,11 +8,10 @@
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/protector/base_setting_change.h"
 #include "content/public/browser/notification_observer.h"
 
-class PrefSetObserver;
-
 namespace protector {
 
 // BaseSettingChange subclass for PrefService-managed settings changes.
@@ -41,7 +40,7 @@ class BasePrefsChange : public BaseSettingChange,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
-  scoped_ptr<PrefSetObserver> pref_observer_;
+  PrefChangeRegistrar pref_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(BasePrefsChange);
 };
diff --git a/chrome/browser/protector/protected_prefs_watcher.cc b/chrome/browser/protector/protected_prefs_watcher.cc
index 80dd4a0..b98438d 100644
--- a/chrome/browser/protector/protected_prefs_watcher.cc
+++ b/chrome/browser/protector/protected_prefs_watcher.cc
@@ -9,8 +9,8 @@
 #include "base/metrics/histogram.h"
 #include "base/stringprintf.h"
 #include "base/values.h"
+#include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/prefs/pref_service.h"
-#include "chrome/browser/prefs/pref_set_observer.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/profiles/profile.h"
@@ -109,8 +109,19 @@ ProtectedPrefsWatcher::ProtectedPrefsWatcher(Profile* profile)
   // Perform necessary pref migrations before actually starting to observe
   // pref changes, otherwise the migration would affect the backup data as well.
   EnsurePrefsMigration();
-  pref_observer_.reset(PrefSetObserver::CreateProtectedPrefSetObserver(
-      profile->GetPrefs(), this));
+
+  pref_observer_.Init(profile->GetPrefs());
+  pref_observer_.Add(prefs::kHomePageIsNewTabPage, this);
+  pref_observer_.Add(prefs::kHomePage, this);
+  pref_observer_.Add(prefs::kShowHomeButton, this);
+  // Session startup.
+  pref_observer_.Add(prefs::kRestoreOnStartup, this);
+  pref_observer_.Add(prefs::kURLsToRestoreOnStartup, this);
+  // Pinned tabs.
+  pref_observer_.Add(prefs::kPinnedTabs, this);
+  // Extensions.
+  pref_observer_.Add(ExtensionPrefs::kExtensionsPref, this);
+
   UpdateCachedPrefs();
   ValidateBackup();
   VLOG(1) << "Initialized pref watcher";
@@ -190,7 +201,7 @@ void ProtectedPrefsWatcher::Observe(
     const content::NotificationDetails& details) {
   DCHECK(type == chrome::NOTIFICATION_PREF_CHANGED);
   const std::string* pref_name = content::Details<std::string>(details).ptr();
-  DCHECK(pref_name && pref_observer_->IsObserved(*pref_name));
+  DCHECK(pref_name && pref_observer_.IsObserved(*pref_name));
   if (UpdateBackupEntry(*pref_name))
     UpdateBackupSignature();
 }
diff --git a/chrome/browser/protector/protected_prefs_watcher.h b/chrome/browser/protector/protected_prefs_watcher.h
index 6a785b4..8dc264d 100644
--- a/chrome/browser/protector/protected_prefs_watcher.h
+++ b/chrome/browser/protector/protected_prefs_watcher.h
@@ -9,11 +9,11 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/extensions/extension_prefs.h"
 #include "content/public/browser/notification_observer.h"
 
 class PrefService;
-class PrefSetObserver;
 class Profile;
 
 namespace base {
@@ -93,7 +93,7 @@ class ProtectedPrefsWatcher : public content::NotificationObserver {
   // Cached set of extension IDs. They are not changed as frequently
   extensions::ExtensionIdList cached_extension_ids_;
 
-  scoped_ptr<PrefSetObserver> pref_observer_;
+  PrefChangeRegistrar pref_observer_;
 
   // True if the backup was valid at the profile load time.
   bool is_backup_valid_;
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.cc b/chrome/browser/ui/webui/options/browser_options_handler.cc
index e1ceea1..73ff7f3 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -604,8 +604,8 @@ void BrowserOptionsHandler::InitializeHandler() {
   default_font_size_.Init(prefs::kWebKitDefaultFontSize, prefs, this);
   default_zoom_level_.Init(prefs::kDefaultZoomLevel, prefs, this);
 #if !defined(OS_CHROMEOS)
-  proxy_prefs_.reset(
-      PrefSetObserver::CreateProxyPrefSetObserver(prefs, this));
+  proxy_prefs_.Init(prefs);
+  proxy_prefs_.Add(prefs::kProxy, this);
 #endif  // !defined(OS_CHROMEOS)
 }
 
@@ -857,7 +857,7 @@ void BrowserOptionsHandler::Observe(
     } else if (*pref_name == prefs::kDownloadExtensionsToOpen) {
       SetupAutoOpenFileTypes();
 #if !defined(OS_CHROMEOS)
-    } else if (proxy_prefs_->IsObserved(*pref_name)) {
+    } else if (proxy_prefs_.IsObserved(*pref_name)) {
       SetupProxySettingsSection();
 #endif  // !defined(OS_CHROMEOS)
     } else if ((*pref_name == prefs::kCloudPrintEmail) ||
@@ -1389,8 +1389,8 @@ void BrowserOptionsHandler::SetupProxySettingsSection() {
   bool is_extension_controlled = (proxy_config &&
                                   proxy_config->IsExtensionControlled());
 
-  base::FundamentalValue disabled(proxy_prefs_->IsManaged() ||
-                            is_extension_controlled);
+  base::FundamentalValue disabled(proxy_prefs_.IsManaged() ||
+                                  is_extension_controlled);
 
   // Get the appropriate info string to describe the button.
   string16 label_str;
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.h b/chrome/browser/ui/webui/options/browser_options_handler.h
index e6d5d1c..b0749a3 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.h
+++ b/chrome/browser/ui/webui/options/browser_options_handler.h
@@ -21,7 +21,7 @@
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/system/pointer_device_observer.h"
 #else
-#include "chrome/browser/prefs/pref_set_observer.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #endif  // defined(OS_CHROMEOS)
 
 class AutocompleteController;
@@ -292,7 +292,7 @@ class BrowserOptionsHandler
   DoublePrefMember default_zoom_level_;
 
 #if !defined(OS_CHROMEOS)
-  scoped_ptr<PrefSetObserver> proxy_prefs_;
+  PrefChangeRegistrar proxy_prefs_;
 #endif  // !defined(OS_CHROMEOS)
 
   DISALLOW_COPY_AND_ASSIGN(BrowserOptionsHandler);
diff --git a/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.cc
index 6abee13..7894ff1 100644
--- a/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.cc
@@ -16,7 +16,7 @@
 #include "chrome/browser/chromeos/proxy_cros_settings_parser.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/policy/browser_policy_connector.h"
-#include "chrome/browser/prefs/pref_set_observer.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/chromeos/ui_account_tweaks.h"
 #include "chrome/browser/ui/webui/options/chromeos/accounts_options_handler.h"
@@ -102,8 +102,8 @@ CoreChromeOSOptionsHandler::~CoreChromeOSOptionsHandler() {
 void CoreChromeOSOptionsHandler::InitializeHandler() {
   CoreOptionsHandler::InitializeHandler();
 
-  proxy_prefs_.reset(PrefSetObserver::CreateProxyPrefSetObserver(
-    Profile::FromWebUI(web_ui())->GetPrefs(), this));
+  proxy_prefs_.Init(Profile::FromWebUI(web_ui())->GetPrefs());
+  proxy_prefs_.Add(prefs::kProxy, this);
   // Observe the chromeos::ProxyConfigServiceImpl for changes from the UI.
   PrefProxyConfigTracker* proxy_tracker =
       Profile::FromWebUI(web_ui())->GetProxyConfigTracker();
@@ -206,7 +206,7 @@ void CoreChromeOSOptionsHandler::Observe(
     const PrefService* pref_service = Profile::FromWebUI(web_ui())->GetPrefs();
     std::string* pref_name = content::Details<std::string>(details).ptr();
     if (content::Source<PrefService>(source).ptr() == pref_service &&
-        (proxy_prefs_->IsObserved(*pref_name) ||
+        (proxy_prefs_.IsObserved(*pref_name) ||
          *pref_name == prefs::kUseSharedProxies)) {
       NotifyPrefChanged(prefs::kUseSharedProxies, prefs::kProxy);
       return;
diff --git a/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.h b/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.h
index ff6c6bc..46fa0ee 100644
--- a/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.h
+++ b/chrome/browser/ui/webui/options/chromeos/core_chromeos_options_handler.h
@@ -7,10 +7,9 @@
 
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/ui/webui/options/core_options_handler.h"
 
-class PrefSetObserver;
-
 namespace chromeos {
 namespace options {
 
@@ -43,7 +42,7 @@ class CoreChromeOSOptionsHandler : public ::options::CoreOptionsHandler {
   void NotifySettingsChanged(const std::string* setting_name);
   void NotifyProxyPrefsChanged();
 
-  scoped_ptr<PrefSetObserver> proxy_prefs_;
+  PrefChangeRegistrar proxy_prefs_;
   base::WeakPtrFactory<CoreChromeOSOptionsHandler> pointer_factory_;
 };
 
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index ffacfb1..7d2aee3 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1405,8 +1405,6 @@
         'browser/prefs/pref_notifier_impl.h',
         'browser/prefs/pref_service.cc',
         'browser/prefs/pref_service.h',
-        'browser/prefs/pref_set_observer.cc',
-        'browser/prefs/pref_set_observer.h',
         'browser/prefs/pref_value_map.cc',
         'browser/prefs/pref_value_map.h',
         'browser/prefs/pref_value_store.cc',
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 86aa4e6..13b6db9 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1523,7 +1523,6 @@
         'browser/prefs/pref_model_associator_unittest.cc',
         'browser/prefs/pref_notifier_impl_unittest.cc',
         'browser/prefs/pref_service_unittest.cc',
-        'browser/prefs/pref_set_observer_unittest.cc',
         'browser/prefs/pref_value_map_unittest.cc',
         'browser/prefs/pref_value_store_unittest.cc',
         'browser/prefs/proxy_config_dictionary_unittest.cc',