[Sync] Generalize StringOrdinal to handle ordinal_in_parent field

Rename StringOrdinal to Ordinal, move it to sync/, and templatize it.
Make StringOrdinal be an instantiation of Ordinal that matches its
previous behavior.

Create NodeOrdinal, which is another instantiation of Ordinal for
the ordinal_in_parent field in SyncEntity.

Rework Ordinal to handle arbitrary byte ranges and to simplify the
interpolation code a bit.

Generalize StringOrdinal unit tests for Ordinal.

Update users of StringOrdinal to prepend syncer::.

BUG=145412
TBR=estade@chromium.org,jianli@chromium.org,brettw@chromium.org, 

Review URL: https://chromiumcodereview.appspot.com/10920017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155368 0039d316-1c4b-4281-b951-d872f2087c98

29 files changed, 318 insertions, 281 deletions

diff --git a/chrome/browser/extensions/app_process_apitest.cc b/chrome/browser/extensions/app_process_apitest.cc
index 61170fc..4383fa0 100644
--- a/chrome/browser/extensions/app_process_apitest.cc
+++ b/chrome/browser/extensions/app_process_apitest.cc
@@ -18,7 +18,6 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_file_util.h"
-#include "chrome/common/string_ordinal.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_service.h"
@@ -28,6 +27,7 @@
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/test_navigation_observer.h"
 #include "net/base/mock_host_resolver.h"
+#include "sync/api/string_ordinal.h"
 
 using content::NavigationController;
 using content::RenderViewHost;
@@ -253,7 +253,7 @@ IN_PROC_BROWSER_TEST_F(AppApiTest, BookmarkAppGetsNormalProcess) {
       Extension::FROM_BOOKMARK,
       &error));
   service->OnExtensionInstalled(extension, false,
-                                StringOrdinal::CreateInitialOrdinal());
+                                syncer::StringOrdinal::CreateInitialOrdinal());
   ASSERT_TRUE(extension.get());
   ASSERT_TRUE(extension->from_bookmark());
 
diff --git a/chrome/browser/extensions/app_sync_data.cc b/chrome/browser/extensions/app_sync_data.cc
index d4d24b5..f7ce406 100644
--- a/chrome/browser/extensions/app_sync_data.cc
+++ b/chrome/browser/extensions/app_sync_data.cc
@@ -30,8 +30,8 @@ AppSyncData::AppSyncData(const Extension& extension,
                          bool incognito_enabled,
                          const std::string& notifications_client_id,
                          bool notifications_disabled,
-                         const StringOrdinal& app_launch_ordinal,
-                         const StringOrdinal& page_ordinal)
+                         const syncer::StringOrdinal& app_launch_ordinal,
+                         const syncer::StringOrdinal& page_ordinal)
     : extension_sync_data_(extension, enabled, incognito_enabled),
       notifications_client_id_(notifications_client_id),
       notifications_disabled_(notifications_disabled),
@@ -65,9 +65,9 @@ void AppSyncData::PopulateAppSpecifics(sync_pb::AppSpecifics* specifics) const {
 
   // Only sync the ordinal values if they are valid.
   if (app_launch_ordinal_.IsValid())
-    specifics->set_app_launch_ordinal(app_launch_ordinal_.ToString());
+    specifics->set_app_launch_ordinal(app_launch_ordinal_.ToInternalValue());
   if (page_ordinal_.IsValid())
-    specifics->set_page_ordinal(page_ordinal_.ToString());
+    specifics->set_page_ordinal(page_ordinal_.ToInternalValue());
 
   extension_sync_data_.PopulateExtensionSpecifics(
       specifics->mutable_extension());
@@ -88,8 +88,8 @@ void AppSyncData::PopulateFromAppSpecifics(
       specifics.notification_settings().has_disabled() &&
       specifics.notification_settings().disabled();
 
-  app_launch_ordinal_ = StringOrdinal(specifics.app_launch_ordinal());
-  page_ordinal_ = StringOrdinal(specifics.page_ordinal());
+  app_launch_ordinal_ = syncer::StringOrdinal(specifics.app_launch_ordinal());
+  page_ordinal_ = syncer::StringOrdinal(specifics.page_ordinal());
 }
 
 void AppSyncData::PopulateFromSyncData(const syncer::SyncData& sync_data) {
diff --git a/chrome/browser/extensions/app_sync_data.h b/chrome/browser/extensions/app_sync_data.h
index 455c64c..7e8d0a4 100644
--- a/chrome/browser/extensions/app_sync_data.h
+++ b/chrome/browser/extensions/app_sync_data.h
@@ -6,7 +6,7 @@
 #define CHROME_BROWSER_EXTENSIONS_APP_SYNC_DATA_H_
 
 #include "chrome/browser/extensions/extension_sync_data.h"
-#include "chrome/common/string_ordinal.h"
+#include "sync/api/string_ordinal.h"
 #include "sync/api/sync_change.h"
 
 namespace syncer {
@@ -33,8 +33,8 @@ class AppSyncData {
               bool incognito_enabled,
               const std::string& notifications_client_id,
               bool notifications_disabled,
-              const StringOrdinal& app_launch_ordinal,
-              const StringOrdinal& page_ordinal);
+              const syncer::StringOrdinal& app_launch_ordinal,
+              const syncer::StringOrdinal& page_ordinal);
   ~AppSyncData();
 
   // Retrive sync data from this class.
@@ -56,10 +56,10 @@ class AppSyncData {
 
   // These ordinals aren't necessarily valid. Some applications don't have
   // valid ordinals because they don't appear on the new tab page.
-  const StringOrdinal& app_launch_ordinal() const {
+  const syncer::StringOrdinal& app_launch_ordinal() const {
     return app_launch_ordinal_;
   }
-  const StringOrdinal& page_ordinal() const { return page_ordinal_; }
+  const syncer::StringOrdinal& page_ordinal() const { return page_ordinal_; }
 
   const ExtensionSyncData& extension_sync_data() const {
     return extension_sync_data_;
@@ -77,8 +77,8 @@ class AppSyncData {
   ExtensionSyncData extension_sync_data_;
   std::string notifications_client_id_;
   bool notifications_disabled_;
-  StringOrdinal app_launch_ordinal_;
-  StringOrdinal page_ordinal_;
+  syncer::StringOrdinal app_launch_ordinal_;
+  syncer::StringOrdinal page_ordinal_;
 };
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/app_sync_data_unittest.cc b/chrome/browser/extensions/app_sync_data_unittest.cc
index 18f676f..64a9ab9 100644
--- a/chrome/browser/extensions/app_sync_data_unittest.cc
+++ b/chrome/browser/extensions/app_sync_data_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/extensions/app_sync_data.h"
 
+#include "sync/api/string_ordinal.h"
 #include "sync/protocol/app_specifics.pb.h"
 #include "sync/protocol/sync.pb.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -41,9 +42,9 @@ TEST_F(AppSyncDataTest, SyncDataToExtensionSyncDataForApp) {
   sync_pb::EntitySpecifics entity;
   sync_pb::AppSpecifics* app_specifics = entity.mutable_app();
   app_specifics->set_app_launch_ordinal(
-      StringOrdinal::CreateInitialOrdinal().ToString());
+      syncer::StringOrdinal::CreateInitialOrdinal().ToInternalValue());
   app_specifics->set_page_ordinal(
-      StringOrdinal::CreateInitialOrdinal().ToString());
+      syncer::StringOrdinal::CreateInitialOrdinal().ToInternalValue());
   sync_pb::AppNotificationSettings* notif_settings =
       app_specifics->mutable_notification_settings();
   notif_settings->set_oauth_client_id(kOAuthClientId);
@@ -56,9 +57,9 @@ TEST_F(AppSyncDataTest, SyncDataToExtensionSyncDataForApp) {
 
   AppSyncData app_sync_data(sync_data);
   EXPECT_EQ(app_specifics->app_launch_ordinal(),
-            app_sync_data.app_launch_ordinal().ToString());
+            app_sync_data.app_launch_ordinal().ToInternalValue());
   EXPECT_EQ(app_specifics->page_ordinal(),
-            app_sync_data.page_ordinal().ToString());
+            app_sync_data.page_ordinal().ToInternalValue());
   EXPECT_EQ(notif_settings->oauth_client_id(),
             app_sync_data.notifications_client_id());
   EXPECT_EQ(notif_settings->disabled(),
@@ -71,9 +72,9 @@ TEST_F(AppSyncDataTest, ExtensionSyncDataToSyncDataForApp) {
   sync_pb::EntitySpecifics entity;
   sync_pb::AppSpecifics* input_specifics = entity.mutable_app();
   input_specifics->set_app_launch_ordinal(
-      StringOrdinal::CreateInitialOrdinal().ToString());
+      syncer::StringOrdinal::CreateInitialOrdinal().ToInternalValue());
   input_specifics->set_page_ordinal(
-      StringOrdinal::CreateInitialOrdinal().ToString());
+      syncer::StringOrdinal::CreateInitialOrdinal().ToInternalValue());
   sync_pb::AppNotificationSettings* notif_settings =
       input_specifics->mutable_notification_settings();
   notif_settings->set_oauth_client_id(kOAuthClientId);
diff --git a/chrome/browser/extensions/crx_installer.h b/chrome/browser/extensions/crx_installer.h
index 1cad360..5c9a79e 100644
--- a/chrome/browser/extensions/crx_installer.h
+++ b/chrome/browser/extensions/crx_installer.h
@@ -17,8 +17,8 @@
 #include "chrome/browser/extensions/sandboxed_unpacker.h"
 #include "chrome/browser/extensions/webstore_installer.h"
 #include "chrome/common/extensions/extension.h"
-#include "chrome/common/string_ordinal.h"
 #include "chrome/common/web_apps.h"
+#include "sync/api/string_ordinal.h"
 
 class ExtensionService;
 class SkBitmap;
@@ -161,7 +161,7 @@ class CrxInstaller
     off_store_install_allow_reason_ = reason;
   }
 
-  void set_page_ordinal(const StringOrdinal& page_ordinal) {
+  void set_page_ordinal(const syncer::StringOrdinal& page_ordinal) {
     page_ordinal_ = page_ordinal;
   }
 
@@ -270,7 +270,7 @@ class CrxInstaller
   scoped_refptr<const Extension> extension_;
 
   // The ordinal of the NTP apps page |extension_| will be shown on.
-  StringOrdinal page_ordinal_;
+  syncer::StringOrdinal page_ordinal_;
 
   // A parsed copy of the unmodified original manifest, before any
   // transformations like localization have taken place.
diff --git a/chrome/browser/extensions/extension_browsertest.cc b/chrome/browser/extensions/extension_browsertest.cc
index a529281..7432b42 100644
--- a/chrome/browser/extensions/extension_browsertest.cc
+++ b/chrome/browser/extensions/extension_browsertest.cc
@@ -37,6 +37,7 @@
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/test/browser_test_utils.h"
+#include "sync/api/string_ordinal.h"
 
 using extensions::Extension;
 using extensions::ExtensionCreator;
@@ -128,7 +129,7 @@ const Extension* ExtensionBrowserTest::LoadExtensionWithFlags(
   // are set up with the defaults.
   service->extension_prefs()->OnExtensionInstalled(
       extension, Extension::ENABLED, false,
-      StringOrdinal::CreateInitialOrdinal());
+      syncer::StringOrdinal::CreateInitialOrdinal());
 
   // Toggling incognito or file access will reload the extension, so wait for
   // the reload and grab the new extension instance. The default state is
diff --git a/chrome/browser/extensions/extension_prefs.cc b/chrome/browser/extensions/extension_prefs.cc
index 1a84624..3b536c0 100644
--- a/chrome/browser/extensions/extension_prefs.cc
+++ b/chrome/browser/extensions/extension_prefs.cc
@@ -1401,7 +1401,7 @@ void ExtensionPrefs::OnExtensionInstalled(
     const Extension* extension,
     Extension::State initial_state,
     bool from_webstore,
-    const StringOrdinal& page_ordinal) {
+    const syncer::StringOrdinal& page_ordinal) {
   const std::string& id = extension->id();
   CHECK(Extension::IdIsValid(id));
   ScopedExtensionPrefUpdate update(prefs_, id);
@@ -1439,7 +1439,7 @@ void ExtensionPrefs::OnExtensionInstalled(
   extension_dict->Remove(kRegisteredEvents, NULL);
 
   if (extension->is_app()) {
-    StringOrdinal new_page_ordinal = page_ordinal.IsValid() ?
+    syncer::StringOrdinal new_page_ordinal = page_ordinal.IsValid() ?
         page_ordinal : extension_sorting_->GetNaturalAppPageOrdinal();
     if (!extension_sorting_->GetPageOrdinal(id).IsValid())
       extension_sorting_->SetPageOrdinal(id, new_page_ordinal);
diff --git a/chrome/browser/extensions/extension_prefs.h b/chrome/browser/extensions/extension_prefs.h
index 7da47b6..bc9c2c7 100644
--- a/chrome/browser/extensions/extension_prefs.h
+++ b/chrome/browser/extensions/extension_prefs.h
@@ -19,7 +19,7 @@
 #include "chrome/browser/media_gallery/media_galleries_preferences.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/url_pattern_set.h"
-#include "chrome/common/string_ordinal.h"
+#include "sync/api/string_ordinal.h"
 
 class ExtensionPrefValueMap;
 class ExtensionSorting;
@@ -122,7 +122,7 @@ class ExtensionPrefs : public ContentSettingsStore::Observer,
   void OnExtensionInstalled(const Extension* extension,
                             Extension::State initial_state,
                             bool from_webstore,
-                            const StringOrdinal& page_ordinal);
+                            const syncer::StringOrdinal& page_ordinal);
 
   // Called when an extension is uninstalled, so that prefs get cleaned up.
   void OnExtensionUninstalled(const std::string& extension_id,
diff --git a/chrome/browser/extensions/extension_prefs_unittest.cc b/chrome/browser/extensions/extension_prefs_unittest.cc
index b3ee126..3629494 100644
--- a/chrome/browser/extensions/extension_prefs_unittest.cc
+++ b/chrome/browser/extensions/extension_prefs_unittest.cc
@@ -17,12 +17,12 @@
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
-#include "chrome/common/extensions/permissions/permissions_info.h"
 #include "chrome/common/extensions/permissions/permission_set.h"
-#include "chrome/common/string_ordinal.h"
+#include "chrome/common/extensions/permissions/permissions_info.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/test/mock_notification_observer.h"
+#include "sync/api/string_ordinal.h"
 
 using base::Time;
 using base::TimeDelta;
@@ -741,7 +741,7 @@ class ExtensionPrefsOnExtensionInstalled : public ExtensionPrefsTest {
     EXPECT_FALSE(prefs()->IsExtensionDisabled(extension_->id()));
     prefs()->OnExtensionInstalled(
         extension_.get(), Extension::DISABLED, false,
-        StringOrdinal());
+        syncer::StringOrdinal());
   }
 
   virtual void Verify() {
@@ -760,7 +760,7 @@ class ExtensionPrefsAppDraggedByUser : public ExtensionPrefsTest {
     extension_ = prefs_.AddExtension("on_extension_installed");
     EXPECT_FALSE(prefs()->WasAppDraggedByUser(extension_->id()));
     prefs()->OnExtensionInstalled(extension_.get(), Extension::ENABLED,
-                                  false, StringOrdinal());
+                                  false, syncer::StringOrdinal());
   }
 
   virtual void Verify() {
@@ -922,7 +922,7 @@ void ExtensionPrefsPrepopulatedTest::EnsureExtensionInstalled(Extension *ext) {
   for (size_t i = 0; i < arraysize(extensions); ++i) {
     if (ext == extensions[i] && !installed[i]) {
       prefs()->OnExtensionInstalled(ext, Extension::ENABLED,
-                                    false, StringOrdinal());
+                                    false, syncer::StringOrdinal());
       installed[i] = true;
       break;
     }
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index bbff196..d0a6ca8 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -2127,7 +2127,7 @@ void ExtensionService::UpdateActiveExtensionsInCrashReporter() {
 void ExtensionService::OnExtensionInstalled(
     const Extension* extension,
     bool from_webstore,
-    const StringOrdinal& page_ordinal) {
+    const syncer::StringOrdinal& page_ordinal) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // Ensure extension is deleted unless we transfer ownership.
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index 0d461da..bc075b3 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -39,6 +39,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "sync/api/string_ordinal.h"
 #include "sync/api/sync_change.h"
 #include "sync/api/syncable_service.h"
 
@@ -405,7 +406,7 @@ class ExtensionService
   void OnExtensionInstalled(
       const extensions::Extension* extension,
       bool from_webstore,
-      const StringOrdinal& page_ordinal);
+      const syncer::StringOrdinal& page_ordinal);
 
   // Initializes the |extension|'s active permission set and disables the
   // extension if the privilege level has increased (e.g., due to an upgrade).
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index c8224b9..9bf75f0 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -63,7 +63,6 @@
 #include "chrome/common/extensions/permissions/permission_set.h"
 #include "chrome/common/extensions/url_pattern.h"
 #include "chrome/common/pref_names.h"
-#include "chrome/common/string_ordinal.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/browser/dom_storage_context.h"
@@ -81,6 +80,7 @@
 #include "net/cookies/cookie_options.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "sync/api/string_ordinal.h"
 #include "sync/api/sync_error_factory.h"
 #include "sync/api/sync_error_factory_mock.h"
 #include "sync/protocol/app_specifics.pb.h"
@@ -2104,8 +2104,9 @@ TEST_F(ExtensionServiceTest, UpdateAppsRetainOrdinals) {
   ASSERT_EQ(std::string("1"), extension->version()->GetString());
 
   // Modify the ordinals so we can distinguish them from the defaults.
-  StringOrdinal new_page_ordinal = sorting->GetPageOrdinal(id).CreateAfter();
-  StringOrdinal new_launch_ordinal =
+  syncer::StringOrdinal new_page_ordinal =
+      sorting->GetPageOrdinal(id).CreateAfter();
+  syncer::StringOrdinal new_launch_ordinal =
       sorting->GetAppLaunchOrdinal(id).CreateBefore();
 
   sorting->SetPageOrdinal(id, new_page_ordinal);
@@ -2117,8 +2118,8 @@ TEST_F(ExtensionServiceTest, UpdateAppsRetainOrdinals) {
             service_->GetExtensionById(id, false)->version()->GetString());
 
   // Verify that the ordinals match.
-  ASSERT_TRUE(new_page_ordinal.Equal(sorting->GetPageOrdinal(id)));
-  ASSERT_TRUE(new_launch_ordinal.Equal(sorting->GetAppLaunchOrdinal(id)));
+  ASSERT_TRUE(new_page_ordinal.Equals(sorting->GetPageOrdinal(id)));
+  ASSERT_TRUE(new_launch_ordinal.Equals(sorting->GetAppLaunchOrdinal(id)));
 }
 
 // Ensures that the CWS has properly initialized ordinals.
@@ -4562,14 +4563,15 @@ TEST_F(ExtensionServiceTest, GetSyncAppDataUserSettings) {
       scoped_ptr<syncer::SyncChangeProcessor>(new TestSyncProcessorStub),
       scoped_ptr<syncer::SyncErrorFactory>(new syncer::SyncErrorFactoryMock()));
 
-  StringOrdinal initial_ordinal = StringOrdinal::CreateInitialOrdinal();
+  syncer::StringOrdinal initial_ordinal =
+      syncer::StringOrdinal::CreateInitialOrdinal();
   {
     syncer::SyncDataList list = service_->GetAllSyncData(syncer::APPS);
     ASSERT_EQ(list.size(), 1U);
 
     extensions::AppSyncData app_sync_data(list[0]);
-    EXPECT_TRUE(initial_ordinal.Equal(app_sync_data.app_launch_ordinal()));
-    EXPECT_TRUE(initial_ordinal.Equal(app_sync_data.page_ordinal()));
+    EXPECT_TRUE(initial_ordinal.Equals(app_sync_data.app_launch_ordinal()));
+    EXPECT_TRUE(initial_ordinal.Equals(app_sync_data.page_ordinal()));
   }
 
   ExtensionSorting* sorting = service_->extension_prefs()->extension_sorting();
@@ -4580,7 +4582,7 @@ TEST_F(ExtensionServiceTest, GetSyncAppDataUserSettings) {
 
     extensions::AppSyncData app_sync_data(list[0]);
     EXPECT_TRUE(initial_ordinal.LessThan(app_sync_data.app_launch_ordinal()));
-    EXPECT_TRUE(initial_ordinal.Equal(app_sync_data.page_ordinal()));
+    EXPECT_TRUE(initial_ordinal.Equals(app_sync_data.page_ordinal()));
   }
 
   sorting->SetPageOrdinal(app->id(), initial_ordinal.CreateAfter());
@@ -4624,7 +4626,7 @@ TEST_F(ExtensionServiceTest, GetSyncAppDataUserSettingsOnExtensionMoved) {
     // The sync data is not always in the same order our apps were installed in,
     // so we do that sorting here so we can make sure the values are changed as
     // expected.
-    StringOrdinal app_launch_ordinals[kAppCount];
+    syncer::StringOrdinal app_launch_ordinals[kAppCount];
     for (size_t i = 0; i < kAppCount; ++i) {
       for (size_t j = 0; j < kAppCount; ++j) {
         if (apps[i]->id() == data[j].id())
diff --git a/chrome/browser/extensions/extension_sorting.cc b/chrome/browser/extensions/extension_sorting.cc
index 07f7de5..9a0dc69 100644
--- a/chrome/browser/extensions/extension_sorting.cc
+++ b/chrome/browser/extensions/extension_sorting.cc
@@ -54,10 +54,11 @@ void ExtensionSorting::CreateOrdinalsIfNecessary(size_t minimum_size) {
   // Create StringOrdinal values as required to ensure |ntp_ordinal_map_| has at
   // least |minimum_size| entries.
   if (ntp_ordinal_map_.empty() && minimum_size > 0)
-    ntp_ordinal_map_[StringOrdinal::CreateInitialOrdinal()];
+    ntp_ordinal_map_[syncer::StringOrdinal::CreateInitialOrdinal()];
 
   while (ntp_ordinal_map_.size() < minimum_size) {
-    StringOrdinal filler = ntp_ordinal_map_.rbegin()->first.CreateAfter();
+    syncer::StringOrdinal filler =
+        ntp_ordinal_map_.rbegin()->first.CreateAfter();
     AppLaunchOrdinalMap empty_ordinal_map;
     ntp_ordinal_map_.insert(std::make_pair(filler, empty_ordinal_map));
   }
@@ -71,13 +72,13 @@ void ExtensionSorting::MigrateAppIndex(
   // Convert all the page index values to page ordinals. If there are any
   // app launch values that need to be migrated, inserted them into a sorted
   // set to be dealt with later.
-  typedef std::map<StringOrdinal, std::map<int, const std::string*>,
-      StringOrdinalLessThan> AppPositionToIdMapping;
+  typedef std::map<syncer::StringOrdinal, std::map<int, const std::string*>,
+                   syncer::StringOrdinal::LessThanFn> AppPositionToIdMapping;
   AppPositionToIdMapping app_launches_to_convert;
   for (ExtensionPrefs::ExtensionIds::const_iterator ext_id =
            extension_ids.begin(); ext_id != extension_ids.end(); ++ext_id) {
     int old_page_index = 0;
-    StringOrdinal page = GetPageOrdinal(*ext_id);
+    syncer::StringOrdinal page = GetPageOrdinal(*ext_id);
     if (extension_scoped_prefs_->ReadExtensionPrefInteger(
             *ext_id,
             kPrefPageIndexDeprecated,
@@ -141,7 +142,7 @@ void ExtensionSorting::MigrateAppIndex(
   for (AppPositionToIdMapping::const_iterator page_it =
            app_launches_to_convert.begin();
        page_it != app_launches_to_convert.end(); ++page_it) {
-    StringOrdinal page = page_it->first;
+    syncer::StringOrdinal page = page_it->first;
     for (std::map<int, const std::string*>::const_iterator launch_it =
             page_it->second.begin(); launch_it != page_it->second.end();
         ++launch_it) {
@@ -164,7 +165,7 @@ void ExtensionSorting::FixNTPOrdinalCollisions() {
         continue;
       }
 
-      StringOrdinal repeated_ordinal = app_launch_it->first;
+      syncer::StringOrdinal repeated_ordinal = app_launch_it->first;
 
       // Sort the conflicting keys by their extension id, this is how
       // the order is decided.
@@ -173,15 +174,15 @@ void ExtensionSorting::FixNTPOrdinalCollisions() {
         conflicting_ids.push_back(app_launch_it->second);
       std::sort(conflicting_ids.begin(), conflicting_ids.end());
 
-      StringOrdinal upper_bound_ordinal = app_launch_it == page.end() ?
-          StringOrdinal() :
+      syncer::StringOrdinal upper_bound_ordinal = app_launch_it == page.end() ?
+          syncer::StringOrdinal() :
           app_launch_it->first;
-      StringOrdinal lower_bound_ordinal = repeated_ordinal;
+      syncer::StringOrdinal lower_bound_ordinal = repeated_ordinal;
 
       // Start at position 1 because the first extension can keep the conflicted
       // value.
       for (int i = 1; i < app_count; ++i) {
-        StringOrdinal unique_app_launch;
+        syncer::StringOrdinal unique_app_launch;
         if (upper_bound_ordinal.IsValid()) {
           unique_app_launch =
               lower_bound_ordinal.CreateBetween(upper_bound_ordinal);
@@ -202,7 +203,7 @@ void ExtensionSorting::FixNTPOrdinalCollisions() {
 }
 
 void ExtensionSorting::EnsureValidOrdinals(const std::string& extension_id) {
-  StringOrdinal page_ordinal = GetPageOrdinal(extension_id);
+  syncer::StringOrdinal page_ordinal = GetPageOrdinal(extension_id);
   if (!page_ordinal.IsValid()) {
     // The webstore app should always start be on the first page.
     page_ordinal = extension_id == extension_misc::kWebStoreAppId ?
@@ -211,7 +212,7 @@ void ExtensionSorting::EnsureValidOrdinals(const std::string& extension_id) {
     SetPageOrdinal(extension_id, page_ordinal);
   }
 
-  StringOrdinal app_launch_ordinal = GetAppLaunchOrdinal(extension_id);
+  syncer::StringOrdinal app_launch_ordinal = GetAppLaunchOrdinal(extension_id);
   if (!app_launch_ordinal.IsValid()) {
     // The webstore app should always start in the position.
     app_launch_ordinal = extension_id == extension_misc::kWebStoreAppId ?
@@ -240,9 +241,9 @@ void ExtensionSorting::OnExtensionMoved(
           GetAppLaunchOrdinal(predecessor_extension_id).CreateAfter());
     } else {
       // Both a successor and predecessor
-      const StringOrdinal& predecessor_ordinal =
+      const syncer::StringOrdinal& predecessor_ordinal =
           GetAppLaunchOrdinal(predecessor_extension_id);
-      const StringOrdinal& successor_ordinal =
+      const syncer::StringOrdinal& successor_ordinal =
           GetAppLaunchOrdinal(successor_extension_id);
       SetAppLaunchOrdinal(moved_extension_id,
                           predecessor_ordinal.CreateBetween(successor_ordinal));
@@ -256,7 +257,7 @@ void ExtensionSorting::OnExtensionMoved(
 }
 
 
-StringOrdinal ExtensionSorting::GetAppLaunchOrdinal(
+syncer::StringOrdinal ExtensionSorting::GetAppLaunchOrdinal(
     const std::string& extension_id) const {
   std::string raw_value;
   // If the preference read fails then raw_value will still be unset and we
@@ -264,25 +265,25 @@ StringOrdinal ExtensionSorting::GetAppLaunchOrdinal(
   // was found.
   extension_scoped_prefs_->ReadExtensionPrefString(
       extension_id, kPrefAppLaunchOrdinal, &raw_value);
-  return StringOrdinal(raw_value);
+  return syncer::StringOrdinal(raw_value);
 }
 
 void ExtensionSorting::SetAppLaunchOrdinal(
     const std::string& extension_id,
-    const StringOrdinal& new_app_launch_ordinal) {
+    const syncer::StringOrdinal& new_app_launch_ordinal) {
   // No work is required if the old and new values are the same.
-  if (new_app_launch_ordinal.EqualOrBothInvalid(
+  if (new_app_launch_ordinal.EqualsOrBothInvalid(
           GetAppLaunchOrdinal(extension_id))) {
     return;
   }
 
-  StringOrdinal page_ordinal = GetPageOrdinal(extension_id);
+  syncer::StringOrdinal page_ordinal = GetPageOrdinal(extension_id);
   RemoveOrdinalMapping(
       extension_id, page_ordinal, GetAppLaunchOrdinal(extension_id));
   AddOrdinalMapping(extension_id, page_ordinal, new_app_launch_ordinal);
 
   Value* new_value = new_app_launch_ordinal.IsValid() ?
-      Value::CreateStringValue(new_app_launch_ordinal.ToString()) :
+      Value::CreateStringValue(new_app_launch_ordinal.ToInternalValue()) :
       NULL;
 
   extension_scoped_prefs_->UpdateExtensionPref(
@@ -292,48 +293,48 @@ void ExtensionSorting::SetAppLaunchOrdinal(
   SyncIfNeeded(extension_id);
 }
 
-StringOrdinal ExtensionSorting::CreateFirstAppLaunchOrdinal(
-    const StringOrdinal& page_ordinal) const {
-  const StringOrdinal& min_ordinal =
+syncer::StringOrdinal ExtensionSorting::CreateFirstAppLaunchOrdinal(
+    const syncer::StringOrdinal& page_ordinal) const {
+  const syncer::StringOrdinal& min_ordinal =
       GetMinOrMaxAppLaunchOrdinalsOnPage(page_ordinal,
                                          ExtensionSorting::MIN_ORDINAL);
 
   if (min_ordinal.IsValid())
     return min_ordinal.CreateBefore();
   else
-    return StringOrdinal::CreateInitialOrdinal();
+    return syncer::StringOrdinal::CreateInitialOrdinal();
 }
 
-StringOrdinal ExtensionSorting::CreateNextAppLaunchOrdinal(
-    const StringOrdinal& page_ordinal) const {
-  const StringOrdinal& max_ordinal =
+syncer::StringOrdinal ExtensionSorting::CreateNextAppLaunchOrdinal(
+    const syncer::StringOrdinal& page_ordinal) const {
+  const syncer::StringOrdinal& max_ordinal =
       GetMinOrMaxAppLaunchOrdinalsOnPage(page_ordinal,
                                          ExtensionSorting::MAX_ORDINAL);
 
   if (max_ordinal.IsValid())
     return max_ordinal.CreateAfter();
   else
-    return StringOrdinal::CreateInitialOrdinal();
+    return syncer::StringOrdinal::CreateInitialOrdinal();
 }
 
-StringOrdinal ExtensionSorting::CreateFirstAppPageOrdinal() const {
+syncer::StringOrdinal ExtensionSorting::CreateFirstAppPageOrdinal() const {
   const DictionaryValue* extensions = pref_service_->GetDictionary(
           ExtensionPrefs::kExtensionsPref);
   CHECK(extensions);
 
   if (ntp_ordinal_map_.empty())
-    return StringOrdinal::CreateInitialOrdinal();
+    return syncer::StringOrdinal::CreateInitialOrdinal();
 
   return ntp_ordinal_map_.begin()->first;
 }
 
-StringOrdinal ExtensionSorting::GetNaturalAppPageOrdinal() const {
+syncer::StringOrdinal ExtensionSorting::GetNaturalAppPageOrdinal() const {
   const DictionaryValue* extensions = pref_service_->GetDictionary(
           ExtensionPrefs::kExtensionsPref);
   CHECK(extensions);
 
   if (ntp_ordinal_map_.empty())
-    return StringOrdinal::CreateInitialOrdinal();
+    return syncer::StringOrdinal::CreateInitialOrdinal();
 
   for (PageOrdinalMap::const_iterator it = ntp_ordinal_map_.begin();
        it != ntp_ordinal_map_.end(); ++it) {
@@ -342,33 +343,34 @@ StringOrdinal ExtensionSorting::GetNaturalAppPageOrdinal() const {
   }
 
   // Add a new page as all existing pages are full.
-  StringOrdinal last_element = ntp_ordinal_map_.rbegin()->first;
+  syncer::StringOrdinal last_element = ntp_ordinal_map_.rbegin()->first;
   return last_element.CreateAfter();
 }
 
-StringOrdinal ExtensionSorting::GetPageOrdinal(const std::string& extension_id)
-    const {
+syncer::StringOrdinal ExtensionSorting::GetPageOrdinal(
+    const std::string& extension_id) const {
   std::string raw_data;
   // If the preference read fails then raw_data will still be unset and we will
   // return an invalid StringOrdinal to signal that no page ordinal was found.
   extension_scoped_prefs_->ReadExtensionPrefString(
       extension_id, kPrefPageOrdinal, &raw_data);
-  return StringOrdinal(raw_data);
+  return syncer::StringOrdinal(raw_data);
 }
 
-void ExtensionSorting::SetPageOrdinal(const std::string& extension_id,
-                                      const StringOrdinal& new_page_ordinal) {
+void ExtensionSorting::SetPageOrdinal(
+    const std::string& extension_id,
+    const syncer::StringOrdinal& new_page_ordinal) {
   // No work is required if the old and new values are the same.
-  if (new_page_ordinal.EqualOrBothInvalid(GetPageOrdinal(extension_id)))
+  if (new_page_ordinal.EqualsOrBothInvalid(GetPageOrdinal(extension_id)))
     return;
 
-  StringOrdinal app_launch_ordinal = GetAppLaunchOrdinal(extension_id);
+  syncer::StringOrdinal app_launch_ordinal = GetAppLaunchOrdinal(extension_id);
   RemoveOrdinalMapping(
       extension_id, GetPageOrdinal(extension_id), app_launch_ordinal);
   AddOrdinalMapping(extension_id, new_page_ordinal, app_launch_ordinal);
 
   Value* new_value = new_page_ordinal.IsValid() ?
-      Value::CreateStringValue(new_page_ordinal.ToString()) :
+      Value::CreateStringValue(new_page_ordinal.ToInternalValue()) :
       NULL;
 
   extension_scoped_prefs_->UpdateExtensionPref(
@@ -390,7 +392,7 @@ void ExtensionSorting::ClearOrdinals(const std::string& extension_id) {
 }
 
 int ExtensionSorting::PageStringOrdinalAsInteger(
-    const StringOrdinal& page_ordinal) const {
+    const syncer::StringOrdinal& page_ordinal) const {
   if (!page_ordinal.IsValid())
     return -1;
 
@@ -399,12 +401,13 @@ int ExtensionSorting::PageStringOrdinalAsInteger(
       std::distance(ntp_ordinal_map_.begin(), it) : -1;
 }
 
-StringOrdinal ExtensionSorting::PageIntegerAsStringOrdinal(size_t page_index) {
+syncer::StringOrdinal ExtensionSorting::PageIntegerAsStringOrdinal(
+    size_t page_index) {
   const DictionaryValue* extensions = pref_service_->GetDictionary(
           ExtensionPrefs::kExtensionsPref);
 
   if (!extensions)
-    return StringOrdinal();
+    return syncer::StringOrdinal();
 
   if (page_index < ntp_ordinal_map_.size()) {
     PageOrdinalMap::const_iterator it = ntp_ordinal_map_.begin();
@@ -416,12 +419,12 @@ StringOrdinal ExtensionSorting::PageIntegerAsStringOrdinal(size_t page_index) {
   return ntp_ordinal_map_.rbegin()->first;
 }
 
-StringOrdinal ExtensionSorting::GetMinOrMaxAppLaunchOrdinalsOnPage(
-    const StringOrdinal& target_page_ordinal,
+syncer::StringOrdinal ExtensionSorting::GetMinOrMaxAppLaunchOrdinalsOnPage(
+    const syncer::StringOrdinal& target_page_ordinal,
     AppLaunchOrdinalReturn return_type) const {
   CHECK(target_page_ordinal.IsValid());
 
-  StringOrdinal return_value;
+  syncer::StringOrdinal return_value;
 
   PageOrdinalMap::const_iterator page =
       ntp_ordinal_map_.find(target_page_ordinal);
@@ -429,7 +432,7 @@ StringOrdinal ExtensionSorting::GetMinOrMaxAppLaunchOrdinalsOnPage(
     const AppLaunchOrdinalMap& app_list = page->second;
 
     if (app_list.empty())
-      return StringOrdinal();
+      return syncer::StringOrdinal();
 
     if (return_type == ExtensionSorting::MAX_ORDINAL)
       return_value = app_list.rbegin()->first;
@@ -454,7 +457,7 @@ void ExtensionSorting::InitializePageOrdinalMap(
   }
 
   // Include the Web Store App since it is displayed on the NTP.
-  StringOrdinal web_store_app_page =
+  syncer::StringOrdinal web_store_app_page =
       GetPageOrdinal(extension_misc::kWebStoreAppId);
   if (web_store_app_page.IsValid()) {
     AddOrdinalMapping(extension_misc::kWebStoreAppId,
@@ -465,8 +468,8 @@ void ExtensionSorting::InitializePageOrdinalMap(
 
 void ExtensionSorting::AddOrdinalMapping(
     const std::string& extension_id,
-    const StringOrdinal& page_ordinal,
-    const StringOrdinal& app_launch_ordinal) {
+    const syncer::StringOrdinal& page_ordinal,
+    const syncer::StringOrdinal& app_launch_ordinal) {
   if (!page_ordinal.IsValid() || !app_launch_ordinal.IsValid())
     return;
 
@@ -476,8 +479,8 @@ void ExtensionSorting::AddOrdinalMapping(
 
 void ExtensionSorting::RemoveOrdinalMapping(
     const std::string& extension_id,
-    const StringOrdinal& page_ordinal,
-    const StringOrdinal& app_launch_ordinal) {
+    const syncer::StringOrdinal& page_ordinal,
+    const syncer::StringOrdinal& app_launch_ordinal) {
   if (!page_ordinal.IsValid() || !app_launch_ordinal.IsValid())
     return;
 
diff --git a/chrome/browser/extensions/extension_sorting.h b/chrome/browser/extensions/extension_sorting.h
index 15d6023..89c19b8 100644
--- a/chrome/browser/extensions/extension_sorting.h
+++ b/chrome/browser/extensions/extension_sorting.h
@@ -9,9 +9,9 @@
 #include <string>
 
 #include "base/basictypes.h"
-#include "chrome/common/extensions/extension.h"
 #include "chrome/browser/extensions/extension_prefs.h"
-#include "chrome/common/string_ordinal.h"
+#include "chrome/common/extensions/extension.h"
+#include "sync/api/string_ordinal.h"
 
 class ExtensionScopedPrefs;
 class ExtensionServiceInterface;
@@ -53,49 +53,51 @@ class ExtensionSorting {
   // apps are on the same page). A string value close to |a*| generally
   // indicates top left. If the extension has no launch ordinal, an invalid
   // StringOrdinal is returned.
-  StringOrdinal GetAppLaunchOrdinal(const std::string& extension_id) const;
+  syncer::StringOrdinal GetAppLaunchOrdinal(
+      const std::string& extension_id) const;
 
   // Sets a specific launch ordinal for an app with |extension_id|.
   void SetAppLaunchOrdinal(const std::string& extension_id,
-                           const StringOrdinal& new_app_launch_ordinal);
+                           const syncer::StringOrdinal& new_app_launch_ordinal);
 
   // Returns a StringOrdinal that is lower than any app launch ordinal for the
   // given page.
-  StringOrdinal CreateFirstAppLaunchOrdinal(const StringOrdinal& page_ordinal)
-      const;
+  syncer::StringOrdinal CreateFirstAppLaunchOrdinal(
+      const syncer::StringOrdinal& page_ordinal) const;
 
   // Returns a StringOrdinal that is higher than any app launch ordinal for the
   // given page.
-  StringOrdinal CreateNextAppLaunchOrdinal(const StringOrdinal& page_ordinal)
-      const;
+  syncer::StringOrdinal CreateNextAppLaunchOrdinal(
+      const syncer::StringOrdinal& page_ordinal) const;
 
   // Returns a StringOrdinal that is lower than any existing page ordinal.
-  StringOrdinal CreateFirstAppPageOrdinal() const;
+  syncer::StringOrdinal CreateFirstAppPageOrdinal() const;
 
   // Gets the page a new app should install to, which is the earliest non-full
   // page.  The returned ordinal may correspond to a page that doesn't yet exist
   // if all pages are full.
-  StringOrdinal GetNaturalAppPageOrdinal() const;
+  syncer::StringOrdinal GetNaturalAppPageOrdinal() const;
 
   // Get the page ordinal for an app with |extension_id|. This determines
   // which page an app will appear on in page-based NTPs.  If the app has no
   // page specified, an invalid StringOrdinal is returned.
-  StringOrdinal GetPageOrdinal(const std::string& extension_id) const;
+  syncer::StringOrdinal GetPageOrdinal(const std::string& extension_id) const;
 
   // Sets a specific page ordinal for an app with |extension_id|.
   void SetPageOrdinal(const std::string& extension_id,
-                      const StringOrdinal& new_page_ordinal);
+                      const syncer::StringOrdinal& new_page_ordinal);
 
   // Removes the ordinal values for an app.
   void ClearOrdinals(const std::string& extension_id);
 
   // Convert the page StringOrdinal value to its integer equivalent. This takes
   // O(# of apps) worst-case.
-  int PageStringOrdinalAsInteger(const StringOrdinal& page_ordinal) const;
+  int PageStringOrdinalAsInteger(
+      const syncer::StringOrdinal& page_ordinal) const;
 
   // Converts the page index integer to its StringOrdinal equivalent. This takes
   // O(# of apps) worst-case.
-  StringOrdinal PageIntegerAsStringOrdinal(size_t page_index);
+  syncer::StringOrdinal PageIntegerAsStringOrdinal(size_t page_index);
 
  private:
   // Unit tests.
@@ -112,8 +114,8 @@ class ExtensionSorting {
   // the largest ordinal on |page_ordinal|. If there are no apps on the page
   // then an invalid StringOrdinal is returned. It is an error to call this
   // function with an invalid |page_ordinal|.
-  StringOrdinal GetMinOrMaxAppLaunchOrdinalsOnPage(
-      const StringOrdinal& page_ordinal,
+  syncer::StringOrdinal GetMinOrMaxAppLaunchOrdinalsOnPage(
+      const syncer::StringOrdinal& page_ordinal,
       AppLaunchOrdinalReturn return_type) const;
 
   // Initialize the |page_ordinal_map_| with the page ordinals used by the
@@ -129,8 +131,8 @@ class ExtensionSorting {
   // of |page_ordinal| and a app launch ordinal of |app_launch_ordinal|. This
   // works with valid and invalid StringOrdinals.
   void AddOrdinalMapping(const std::string& extension_id,
-                         const StringOrdinal& page_ordinal,
-                         const StringOrdinal& app_launch_ordinal);
+                         const syncer::StringOrdinal& page_ordinal,
+                         const syncer::StringOrdinal& app_launch_ordinal);
 
   // Ensures |ntp_ordinal_map_| is of |minimum_size| number of entries.
   void CreateOrdinalsIfNecessary(size_t minimum_size);
@@ -140,8 +142,8 @@ class ExtensionSorting {
   // is not matching map, nothing happens. This works with valid and invalid
   // StringOrdinals.
   void RemoveOrdinalMapping(const std::string& extension_id,
-                            const StringOrdinal& page_ordinal,
-                            const StringOrdinal& app_launch_ordinal);
+                            const syncer::StringOrdinal& page_ordinal,
+                            const syncer::StringOrdinal& app_launch_ordinal);
 
   // Syncs the extension if needed. It is an error to call this if the
   // extension is not an application.
@@ -161,11 +163,13 @@ class ExtensionSorting {
   // The StringOrdinal is the app launch ordinal and the string is the extension
   // id.
   typedef std::multimap<
-      StringOrdinal, std::string, StringOrdinalLessThan> AppLaunchOrdinalMap;
+      syncer::StringOrdinal, std::string,
+    syncer::StringOrdinal::LessThanFn> AppLaunchOrdinalMap;
   // The StringOrdinal is the page ordinal and the AppLaunchOrdinalMap is the
   // contents of that page.
   typedef std::map<
-      StringOrdinal, AppLaunchOrdinalMap, StringOrdinalLessThan> PageOrdinalMap;
+      syncer::StringOrdinal, AppLaunchOrdinalMap,
+    syncer::StringOrdinal::LessThanFn> PageOrdinalMap;
   PageOrdinalMap ntp_ordinal_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSorting);
diff --git a/chrome/browser/extensions/extension_sorting_unittest.cc b/chrome/browser/extensions/extension_sorting_unittest.cc
index 2388abb..9f14a50 100644
--- a/chrome/browser/extensions/extension_sorting_unittest.cc
+++ b/chrome/browser/extensions/extension_sorting_unittest.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/extensions/extension_prefs_unittest.h"
 #include "chrome/browser/extensions/extension_sorting.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
+#include "sync/api/string_ordinal.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using extensions::Extension;
@@ -24,7 +25,7 @@ class ExtensionSortingAppLocation : public ExtensionSortingTest {
     extension_ = prefs_.AddExtension("not_an_app");
     // Non-apps should not have any app launch ordinal or page ordinal.
     prefs()->OnExtensionInstalled(extension_.get(), Extension::ENABLED,
-                                  false, StringOrdinal());
+                                  false, syncer::StringOrdinal());
   }
 
   virtual void Verify() OVERRIDE {
@@ -43,20 +44,21 @@ class ExtensionSortingAppLaunchOrdinal : public ExtensionSortingTest {
  public:
   virtual void Initialize() OVERRIDE {
     // No extensions yet.
-    StringOrdinal page = StringOrdinal::CreateInitialOrdinal();
-    EXPECT_TRUE(StringOrdinal::CreateInitialOrdinal().Equal(
+    syncer::StringOrdinal page = syncer::StringOrdinal::CreateInitialOrdinal();
+    EXPECT_TRUE(syncer::StringOrdinal::CreateInitialOrdinal().Equals(
         extension_sorting()->CreateNextAppLaunchOrdinal(page)));
 
     extension_ = prefs_.AddApp("on_extension_installed");
     EXPECT_FALSE(prefs()->IsExtensionDisabled(extension_->id()));
     prefs()->OnExtensionInstalled(extension_.get(), Extension::ENABLED,
-                                  false, StringOrdinal());
+                                  false, syncer::StringOrdinal());
   }
 
   virtual void Verify() OVERRIDE {
-    StringOrdinal launch_ordinal =
+    syncer::StringOrdinal launch_ordinal =
         extension_sorting()->GetAppLaunchOrdinal(extension_->id());
-    StringOrdinal page_ordinal = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal page_ordinal =
+        syncer::StringOrdinal::CreateInitialOrdinal();
 
     // Extension should have been assigned a valid StringOrdinal.
     EXPECT_TRUE(launch_ordinal.IsValid());
@@ -66,13 +68,13 @@ class ExtensionSortingAppLaunchOrdinal : public ExtensionSortingTest {
     extension_sorting()->SetAppLaunchOrdinal(
         extension_->id(),
         extension_sorting()->CreateNextAppLaunchOrdinal(page_ordinal));
-    StringOrdinal new_launch_ordinal =
+    syncer::StringOrdinal new_launch_ordinal =
         extension_sorting()->GetAppLaunchOrdinal(extension_->id());
     EXPECT_TRUE(launch_ordinal.LessThan(new_launch_ordinal));
 
     // This extension doesn't exist, so it should return an invalid
     // StringOrdinal.
-    StringOrdinal invalid_app_launch_ordinal =
+    syncer::StringOrdinal invalid_app_launch_ordinal =
         extension_sorting()->GetAppLaunchOrdinal("foo");
     EXPECT_FALSE(invalid_app_launch_ordinal.IsValid());
     EXPECT_EQ(-1, extension_sorting()->PageStringOrdinalAsInteger(
@@ -80,10 +82,10 @@ class ExtensionSortingAppLaunchOrdinal : public ExtensionSortingTest {
 
     // The second page doesn't have any apps so its next launch ordinal should
     // be the first launch ordinal.
-    StringOrdinal next_page = page_ordinal.CreateAfter();
-    StringOrdinal next_page_app_launch_ordinal =
+    syncer::StringOrdinal next_page = page_ordinal.CreateAfter();
+    syncer::StringOrdinal next_page_app_launch_ordinal =
         extension_sorting()->CreateNextAppLaunchOrdinal(next_page);
-    EXPECT_TRUE(next_page_app_launch_ordinal.Equal(
+    EXPECT_TRUE(next_page_app_launch_ordinal.Equals(
         extension_sorting()->CreateFirstAppLaunchOrdinal(next_page)));
   }
 
@@ -97,27 +99,27 @@ class ExtensionSortingPageOrdinal : public ExtensionSortingTest {
   virtual void Initialize() OVERRIDE{
     extension_ = prefs_.AddApp("page_ordinal");
     // Install with a page preference.
-    first_page_ = StringOrdinal::CreateInitialOrdinal();
+    first_page_ = syncer::StringOrdinal::CreateInitialOrdinal();
     prefs()->OnExtensionInstalled(extension_.get(), Extension::ENABLED,
                                   false, first_page_);
-    EXPECT_TRUE(first_page_.Equal(
+    EXPECT_TRUE(first_page_.Equals(
         extension_sorting()->GetPageOrdinal(extension_->id())));
     EXPECT_EQ(0, extension_sorting()->PageStringOrdinalAsInteger(first_page_));
 
     scoped_refptr<Extension> extension2 = prefs_.AddApp("page_ordinal_2");
     // Install without any page preference.
     prefs()->OnExtensionInstalled(extension2.get(), Extension::ENABLED,
-                                  false, StringOrdinal());
-    EXPECT_TRUE(first_page_.Equal(
+                                  false, syncer::StringOrdinal());
+    EXPECT_TRUE(first_page_.Equals(
         extension_sorting()->GetPageOrdinal(extension2->id())));
   }
   virtual void Verify() OVERRIDE {
     // Set the page ordinal.
-    StringOrdinal new_page = first_page_.CreateAfter();
+    syncer::StringOrdinal new_page = first_page_.CreateAfter();
     extension_sorting()->SetPageOrdinal(extension_->id(), new_page);
     // Verify the page ordinal.
     EXPECT_TRUE(
-        new_page.Equal(extension_sorting()->GetPageOrdinal(extension_->id())));
+        new_page.Equals(extension_sorting()->GetPageOrdinal(extension_->id())));
     EXPECT_EQ(1, extension_sorting()->PageStringOrdinalAsInteger(new_page));
 
     // This extension doesn't exist, so it should return an invalid
@@ -126,7 +128,7 @@ class ExtensionSortingPageOrdinal : public ExtensionSortingTest {
   }
 
  private:
-  StringOrdinal first_page_;
+  syncer::StringOrdinal first_page_;
   scoped_refptr<Extension> extension_;
 };
 TEST_F(ExtensionSortingPageOrdinal, ExtensionSortingPageOrdinal) {}
@@ -179,19 +181,20 @@ class ExtensionSortingInitialize
     prefs()->extension_sorting()->Initialize(ids);
   }
   virtual void Verify() OVERRIDE {
-    StringOrdinal first_ordinal = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal first_ordinal =
+        syncer::StringOrdinal::CreateInitialOrdinal();
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    EXPECT_TRUE(first_ordinal.Equal(
+    EXPECT_TRUE(first_ordinal.Equals(
         extension_sorting->GetAppLaunchOrdinal(ext1_->id())));
     EXPECT_TRUE(first_ordinal.LessThan(
         extension_sorting->GetAppLaunchOrdinal(ext2_->id())));
-    EXPECT_TRUE(first_ordinal.Equal(
+    EXPECT_TRUE(first_ordinal.Equals(
         extension_sorting->GetAppLaunchOrdinal(ext3_->id())));
 
-    EXPECT_TRUE(first_ordinal.Equal(
+    EXPECT_TRUE(first_ordinal.Equals(
         extension_sorting->GetPageOrdinal(ext1_->id())));
-    EXPECT_TRUE(first_ordinal.Equal(
+    EXPECT_TRUE(first_ordinal.Equals(
         extension_sorting->GetPageOrdinal(ext2_->id())));
     EXPECT_TRUE(first_ordinal.LessThan(
         extension_sorting->GetPageOrdinal(ext3_->id())));
@@ -211,7 +214,8 @@ class ExtensionSortingInitializeWithNoApps
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
     // Make sure that the web store has valid ordinals.
-    StringOrdinal initial_ordinal = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal initial_ordinal =
+        syncer::StringOrdinal::CreateInitialOrdinal();
     extension_sorting->SetPageOrdinal(extension_misc::kWebStoreAppId,
                                       initial_ordinal);
     extension_sorting->SetAppLaunchOrdinal(extension_misc::kWebStoreAppId,
@@ -223,7 +227,7 @@ class ExtensionSortingInitializeWithNoApps
   virtual void Verify() OVERRIDE {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    StringOrdinal page =
+    syncer::StringOrdinal page =
         extension_sorting->GetPageOrdinal(extension_misc::kWebStoreAppId);
     EXPECT_TRUE(page.IsValid());
 
@@ -231,7 +235,7 @@ class ExtensionSortingInitializeWithNoApps
         extension_sorting->ntp_ordinal_map_.find(page);
     EXPECT_TRUE(page_it != extension_sorting->ntp_ordinal_map_.end());
 
-    StringOrdinal app_launch =
+    syncer::StringOrdinal app_launch =
         extension_sorting->GetPageOrdinal(extension_misc::kWebStoreAppId);
     EXPECT_TRUE(app_launch.IsValid());
 
@@ -290,7 +294,7 @@ class ExtensionSortingFixNTPCollisionsAllCollide
   virtual ~ExtensionSortingFixNTPCollisionsAllCollide() {}
 
   virtual void Initialize() OVERRIDE {
-    repeated_ordinal_ = StringOrdinal::CreateInitialOrdinal();
+    repeated_ordinal_ = syncer::StringOrdinal::CreateInitialOrdinal();
 
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
@@ -307,12 +311,12 @@ class ExtensionSortingFixNTPCollisionsAllCollide
   }
   virtual void Verify() OVERRIDE {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
-    StringOrdinal ext1_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext1_->id());
-    StringOrdinal ext2_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext2_->id());
-    StringOrdinal ext3_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext3_->id());
+    syncer::StringOrdinal ext1_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext1_->id());
+    syncer::StringOrdinal ext2_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext2_->id());
+    syncer::StringOrdinal ext3_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext3_->id());
 
     // The overlapping extensions should have be adjusted so that they are
     // sorted by their id.
@@ -324,16 +328,16 @@ class ExtensionSortingFixNTPCollisionsAllCollide
               ext2_app_launch.LessThan(ext3_app_launch));
 
     // The page ordinal should be unchanged.
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equals(
         repeated_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equals(
         repeated_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equals(
         repeated_ordinal_));
   }
 
  private:
-  StringOrdinal repeated_ordinal_;
+  syncer::StringOrdinal repeated_ordinal_;
 };
 TEST_F(ExtensionSortingFixNTPCollisionsAllCollide,
        ExtensionSortingFixNTPCollisionsAllCollide) {}
@@ -345,8 +349,8 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtStart
   virtual ~ExtensionSortingFixNTPCollisionsSomeCollideAtStart() {}
 
   virtual void Initialize() OVERRIDE {
-    first_ordinal_ = StringOrdinal::CreateInitialOrdinal();
-    StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
+    first_ordinal_ = syncer::StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
 
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
@@ -366,12 +370,12 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtStart
   }
   virtual void Verify() OVERRIDE {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
-    StringOrdinal ext1_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext1_->id());
-    StringOrdinal ext2_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext2_->id());
-    StringOrdinal ext3_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext3_->id());
+    syncer::StringOrdinal ext1_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext1_->id());
+    syncer::StringOrdinal ext2_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext2_->id());
+    syncer::StringOrdinal ext3_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext3_->id());
 
     // The overlapping extensions should have be adjusted so that they are
     // sorted by their id, but they both should be before ext3, which wasn't
@@ -382,16 +386,16 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtStart
     EXPECT_TRUE(ext2_app_launch.LessThan(ext3_app_launch));
 
     // The page ordinal should be unchanged.
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equals(
         first_ordinal_));
   }
 
  private:
-  StringOrdinal first_ordinal_;
+  syncer::StringOrdinal first_ordinal_;
 };
 TEST_F(ExtensionSortingFixNTPCollisionsSomeCollideAtStart,
        ExtensionSortingFixNTPCollisionsSomeCollideAtStart) {}
@@ -403,8 +407,8 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtEnd
   virtual ~ExtensionSortingFixNTPCollisionsSomeCollideAtEnd() {}
 
   virtual void Initialize() OVERRIDE {
-    first_ordinal_ = StringOrdinal::CreateInitialOrdinal();
-    StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
+    first_ordinal_ = syncer::StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
 
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
@@ -424,12 +428,12 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtEnd
   }
   virtual void Verify() OVERRIDE {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
-    StringOrdinal ext1_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext1_->id());
-    StringOrdinal ext2_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext2_->id());
-    StringOrdinal ext3_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext3_->id());
+    syncer::StringOrdinal ext1_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext1_->id());
+    syncer::StringOrdinal ext2_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext2_->id());
+    syncer::StringOrdinal ext3_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext3_->id());
 
     // The overlapping extensions should have be adjusted so that they are
     // sorted by their id, but they both should be after ext1, which wasn't
@@ -440,16 +444,16 @@ class ExtensionSortingFixNTPCollisionsSomeCollideAtEnd
               ext2_app_launch.LessThan(ext3_app_launch));
 
     // The page ordinal should be unchanged.
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equals(
         first_ordinal_));
   }
 
  private:
-  StringOrdinal first_ordinal_;
+  syncer::StringOrdinal first_ordinal_;
 };
 TEST_F(ExtensionSortingFixNTPCollisionsSomeCollideAtEnd,
        ExtensionSortingFixNTPCollisionsSomeCollideAtEnd) {}
@@ -461,8 +465,8 @@ class ExtensionSortingFixNTPCollisionsTwoCollisions
   virtual ~ExtensionSortingFixNTPCollisionsTwoCollisions() {}
 
   virtual void Initialize() OVERRIDE {
-    first_ordinal_ = StringOrdinal::CreateInitialOrdinal();
-    StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
+    first_ordinal_ = syncer::StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal second_ordinal = first_ordinal_.CreateAfter();
 
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
@@ -483,14 +487,14 @@ class ExtensionSortingFixNTPCollisionsTwoCollisions
   }
   virtual void Verify() OVERRIDE {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
-    StringOrdinal ext1_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext1_->id());
-    StringOrdinal ext2_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext2_->id());
-    StringOrdinal ext3_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext3_->id());
-    StringOrdinal ext4_app_launch = extension_sorting->GetAppLaunchOrdinal(
-        ext4_->id());
+    syncer::StringOrdinal ext1_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext1_->id());
+    syncer::StringOrdinal ext2_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext2_->id());
+    syncer::StringOrdinal ext3_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext3_->id());
+    syncer::StringOrdinal ext4_app_launch =
+        extension_sorting->GetAppLaunchOrdinal(ext4_->id());
 
     // The overlapping extensions should have be adjusted so that they are
     // sorted by their id, with |ext1| and |ext2| appearing before |ext3| and
@@ -506,18 +510,18 @@ class ExtensionSortingFixNTPCollisionsTwoCollisions
               ext3_app_launch.LessThan(ext4_app_launch));
 
     // The page ordinal should be unchanged.
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext1_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext2_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext3_->id()).Equals(
         first_ordinal_));
-    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext4_->id()).Equal(
+    EXPECT_TRUE(extension_sorting->GetPageOrdinal(ext4_->id()).Equals(
         first_ordinal_));
   }
 
  private:
-  StringOrdinal first_ordinal_;
+  syncer::StringOrdinal first_ordinal_;
 };
 TEST_F(ExtensionSortingFixNTPCollisionsTwoCollisions,
        ExtensionSortingFixNTPCollisionsTwoCollisions) {}
@@ -532,10 +536,11 @@ class ExtensionSortingEnsureValidOrdinals :
   virtual void Verify() {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    // Give ext1 invalid ordinals and then check that EnsureValidOridnals fixes
+    // Give ext1 invalid ordinals and then check that EnsureValidOrdinals fixes
     // them.
-    extension_sorting->SetAppLaunchOrdinal(ext1_->id(), StringOrdinal());
-    extension_sorting->SetPageOrdinal(ext1_->id(), StringOrdinal());
+    extension_sorting->SetAppLaunchOrdinal(ext1_->id(),
+                                           syncer::StringOrdinal());
+    extension_sorting->SetPageOrdinal(ext1_->id(), syncer::StringOrdinal());
 
     extension_sorting->EnsureValidOrdinals(ext1_->id());
 
@@ -558,7 +563,8 @@ class ExtensionSortingPageOrdinalMapping :
     std::string ext_2 = "ext_2";
 
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
-    StringOrdinal first_ordinal = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal first_ordinal =
+        syncer::StringOrdinal::CreateInitialOrdinal();
 
     // Ensure attempting to removing a mapping with an invalid page doesn't
     // modify the map.
@@ -622,7 +628,7 @@ class ExtensionSortingPreinstalledAppsBase :
     prefs()->OnExtensionInstalled(app1_scoped_.get(),
                                   Extension::ENABLED,
                                   false,
-                                  StringOrdinal());
+                                  syncer::StringOrdinal());
 
     app2_scoped_ = Extension::Create(
         prefs_.temp_dir().AppendASCII("app2_"), Extension::EXTERNAL_PREF,
@@ -630,7 +636,7 @@ class ExtensionSortingPreinstalledAppsBase :
     prefs()->OnExtensionInstalled(app2_scoped_.get(),
                                   Extension::ENABLED,
                                   false,
-                                  StringOrdinal());
+                                  syncer::StringOrdinal());
 
     app1_ = app1_scoped_.get();
     app2_ = app2_scoped_.get();
@@ -655,23 +661,25 @@ class ExtensionSortingGetMinOrMaxAppLaunchOrdinalsOnPage :
 
   virtual void Initialize() OVERRIDE {}
   virtual void Verify() OVERRIDE {
-    StringOrdinal page = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal page = syncer::StringOrdinal::CreateInitialOrdinal();
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    StringOrdinal min = extension_sorting->GetMinOrMaxAppLaunchOrdinalsOnPage(
-        page,
-        ExtensionSorting::MIN_ORDINAL);
-    StringOrdinal max = extension_sorting->GetMinOrMaxAppLaunchOrdinalsOnPage(
-        page,
-        ExtensionSorting::MAX_ORDINAL);
+    syncer::StringOrdinal min =
+        extension_sorting->GetMinOrMaxAppLaunchOrdinalsOnPage(
+            page,
+            ExtensionSorting::MIN_ORDINAL);
+    syncer::StringOrdinal max =
+        extension_sorting->GetMinOrMaxAppLaunchOrdinalsOnPage(
+            page,
+            ExtensionSorting::MAX_ORDINAL);
     EXPECT_TRUE(min.IsValid());
     EXPECT_TRUE(max.IsValid());
     EXPECT_TRUE(min.LessThan(max));
 
     // Ensure that the min and max values aren't set for empty pages.
-    min = StringOrdinal();
-    max = StringOrdinal();
-    StringOrdinal empty_page = page.CreateAfter();
+    min = syncer::StringOrdinal();
+    max = syncer::StringOrdinal();
+    syncer::StringOrdinal empty_page = page.CreateAfter();
     EXPECT_FALSE(min.IsValid());
     EXPECT_FALSE(max.IsValid());
     min = extension_sorting->GetMinOrMaxAppLaunchOrdinalsOnPage(
@@ -698,7 +706,8 @@ class ExtensionSortingKeepEmptyStringOrdinalPages :
   virtual void Initialize() {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    StringOrdinal first_page = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal first_page =
+        syncer::StringOrdinal::CreateInitialOrdinal();
     extension_sorting->SetPageOrdinal(app1_->id(), first_page);
     EXPECT_EQ(0, extension_sorting->PageStringOrdinalAsInteger(first_page));
 
@@ -719,11 +728,11 @@ class ExtensionSortingKeepEmptyStringOrdinalPages :
     extension_sorting->SetPageOrdinal(app2_->id(), last_page_);
     EXPECT_EQ(2, extension_sorting->PageStringOrdinalAsInteger(last_page_));
     EXPECT_TRUE(
-        last_page_.Equal(extension_sorting->PageIntegerAsStringOrdinal(2)));
+        last_page_.Equals(extension_sorting->PageIntegerAsStringOrdinal(2)));
   }
 
  private:
-  StringOrdinal last_page_;
+  syncer::StringOrdinal last_page_;
 };
 TEST_F(ExtensionSortingKeepEmptyStringOrdinalPages,
        ExtensionSortingKeepEmptyStringOrdinalPages) {}
@@ -737,7 +746,8 @@ class ExtensionSortingMakesFillerOrdinals :
   virtual void Initialize() {
     ExtensionSorting* extension_sorting = prefs()->extension_sorting();
 
-    StringOrdinal first_page = StringOrdinal::CreateInitialOrdinal();
+    syncer::StringOrdinal first_page =
+        syncer::StringOrdinal::CreateInitialOrdinal();
     extension_sorting->SetPageOrdinal(app1_->id(), first_page);
     EXPECT_EQ(0, extension_sorting->PageStringOrdinalAsInteger(first_page));
   }
@@ -748,11 +758,13 @@ class ExtensionSortingMakesFillerOrdinals :
     // on them, this test simulates dropping of an app on the 1st and 4th empty
     // pages (3rd and 6th pages by index) to ensure we don't crash and that
     // filler ordinals are created as needed. See: http://crbug.com/122214
-    StringOrdinal page_three = extension_sorting->PageIntegerAsStringOrdinal(2);
+    syncer::StringOrdinal page_three =
+        extension_sorting->PageIntegerAsStringOrdinal(2);
     extension_sorting->SetPageOrdinal(app1_->id(), page_three);
     EXPECT_EQ(2, extension_sorting->PageStringOrdinalAsInteger(page_three));
 
-    StringOrdinal page_six = extension_sorting->PageIntegerAsStringOrdinal(5);
+    syncer::StringOrdinal page_six =
+        extension_sorting->PageIntegerAsStringOrdinal(5);
     extension_sorting->SetPageOrdinal(app1_->id(), page_six);
     EXPECT_EQ(5, extension_sorting->PageStringOrdinalAsInteger(page_six));
   }
diff --git a/chrome/browser/extensions/extension_sync_data.h b/chrome/browser/extensions/extension_sync_data.h
index 989924a..cf8ac6d 100644
--- a/chrome/browser/extensions/extension_sync_data.h
+++ b/chrome/browser/extensions/extension_sync_data.h
@@ -8,7 +8,6 @@
 #include <string>
 
 #include "base/version.h"
-#include "chrome/common/string_ordinal.h"
 #include "googleurl/src/gurl.h"
 #include "sync/api/sync_change.h"
 
diff --git a/chrome/browser/extensions/test_extension_prefs.cc b/chrome/browser/extensions/test_extension_prefs.cc
index b28c5fb..43f08bb 100644
--- a/chrome/browser/extensions/test_extension_prefs.cc
+++ b/chrome/browser/extensions/test_extension_prefs.cc
@@ -22,6 +22,7 @@
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "chrome/common/json_pref_store.h"
 #include "content/public/browser/browser_thread.h"
+#include "sync/api/string_ordinal.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::BrowserThread;
@@ -146,7 +147,7 @@ scoped_refptr<Extension> TestExtensionPrefs::AddExtensionWithManifestAndFlags(
   EXPECT_TRUE(Extension::IdIsValid(extension->id()));
   prefs_->OnExtensionInstalled(extension, Extension::ENABLED,
                                extra_flags & Extension::FROM_WEBSTORE,
-                               StringOrdinal::CreateInitialOrdinal());
+                               syncer::StringOrdinal::CreateInitialOrdinal());
   return extension;
 }
 
diff --git a/chrome/browser/extensions/unpacked_installer.cc b/chrome/browser/extensions/unpacked_installer.cc
index 00b7c46..80307c0 100644
--- a/chrome/browser/extensions/unpacked_installer.cc
+++ b/chrome/browser/extensions/unpacked_installer.cc
@@ -15,7 +15,7 @@
 #include "chrome/browser/extensions/permissions_updater.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_file_util.h"
-#include "chrome/common/string_ordinal.h"
+#include "sync/api/string_ordinal.h"
 
 using content::BrowserThread;
 using extensions::Extension;
@@ -67,7 +67,7 @@ void SimpleExtensionLoadPrompt::InstallUIProceed() {
     extensions::PermissionsUpdater perms_updater(service_weak_->profile());
     perms_updater.GrantActivePermissions(extension_, false);
     service_weak_->OnExtensionInstalled(
-        extension_, false, StringOrdinal());  // Not from web store.
+        extension_, false, syncer::StringOrdinal());  // Not from web store.
   }
   delete this;
 }
@@ -237,7 +237,7 @@ void UnpackedInstaller::OnLoaded(
   perms_updater.GrantActivePermissions(extension, false);
   service_weak_->OnExtensionInstalled(extension,
                                       false,  // Not from web store.
-                                      StringOrdinal());
+                                      syncer::StringOrdinal());
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/media_gallery/media_galleries_preferences_unittest.cc b/chrome/browser/media_gallery/media_galleries_preferences_unittest.cc
index 9d3b856..333e529 100644
--- a/chrome/browser/media_gallery/media_galleries_preferences_unittest.cc
+++ b/chrome/browser/media_gallery/media_galleries_preferences_unittest.cc
@@ -22,6 +22,7 @@
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread.h"
+#include "sync/api/string_ordinal.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chrome {
@@ -220,7 +221,7 @@ class MediaGalleriesPreferencesTest : public testing::Test {
 
     extension_service_->extension_prefs()->OnExtensionInstalled(
         extension, extensions::Extension::ENABLED, false,
-        StringOrdinal::CreateInitialOrdinal());
+        syncer::StringOrdinal::CreateInitialOrdinal());
 
     return extension;
   }
diff --git a/chrome/browser/sync/test/integration/apps_helper.cc b/chrome/browser/sync/test/integration/apps_helper.cc
index a73c17d..faf0add 100644
--- a/chrome/browser/sync/test/integration/apps_helper.cc
+++ b/chrome/browser/sync/test/integration/apps_helper.cc
@@ -83,28 +83,29 @@ void InstallAppsPendingForSync(Profile* profile) {
       profile, extensions::Extension::TYPE_HOSTED_APP);
 }
 
-StringOrdinal GetPageOrdinalForApp(Profile* profile,
-                                   int app_index) {
+syncer::StringOrdinal GetPageOrdinalForApp(Profile* profile,
+                                           int app_index) {
   return SyncAppHelper::GetInstance()->GetPageOrdinalForApp(
       profile, CreateFakeAppName(app_index));
 }
 
 void SetPageOrdinalForApp(Profile* profile,
                           int app_index,
-                          const StringOrdinal& page_ordinal) {
+                          const syncer::StringOrdinal& page_ordinal) {
   SyncAppHelper::GetInstance()->SetPageOrdinalForApp(
       profile, CreateFakeAppName(app_index), page_ordinal);
 }
 
-StringOrdinal GetAppLaunchOrdinalForApp(Profile* profile,
-                                        int app_index) {
+syncer::StringOrdinal GetAppLaunchOrdinalForApp(Profile* profile,
+                                                int app_index) {
   return SyncAppHelper::GetInstance()->GetAppLaunchOrdinalForApp(
       profile, CreateFakeAppName(app_index));
 }
 
-void SetAppLaunchOrdinalForApp(Profile* profile,
-                               int app_index,
-                               const StringOrdinal& app_launch_ordinal) {
+void SetAppLaunchOrdinalForApp(
+    Profile* profile,
+    int app_index,
+    const syncer::StringOrdinal& app_launch_ordinal) {
   SyncAppHelper::GetInstance()->SetAppLaunchOrdinalForApp(
       profile, CreateFakeAppName(app_index), app_launch_ordinal);
 }
diff --git a/chrome/browser/sync/test/integration/apps_helper.h b/chrome/browser/sync/test/integration/apps_helper.h
index c98f24b..bd6a968 100644
--- a/chrome/browser/sync/test/integration/apps_helper.h
+++ b/chrome/browser/sync/test/integration/apps_helper.h
@@ -8,7 +8,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
-#include "chrome/common/string_ordinal.h"
+#include "sync/api/string_ordinal.h"
 
 class Profile;
 
@@ -50,21 +50,24 @@ void IncognitoDisableApp(Profile* profile, int index);
 
 // Gets the page ordinal value for the application at the given index on
 // |profile|.
-StringOrdinal GetPageOrdinalForApp(Profile* profile, int app_index);
+syncer::StringOrdinal GetPageOrdinalForApp(Profile* profile, int app_index);
 
 // Sets a new |page_ordinal| value for the application at the given index
 // on |profile|.
 void SetPageOrdinalForApp(
-    Profile* profile, int app_index, const StringOrdinal& page_ordinal);
+    Profile* profile, int app_index,
+    const syncer::StringOrdinal& page_ordinal);
 
 // Gets the app launch ordinal value for the application at the given index on
 // |profile|.
-StringOrdinal GetAppLaunchOrdinalForApp(Profile* profile, int app_index);
+syncer::StringOrdinal GetAppLaunchOrdinalForApp(
+    Profile* profile, int app_index);
 
 // Sets a new |page_ordinal| value for the application at the given index
 // on |profile|.
 void SetAppLaunchOrdinalForApp(
-    Profile* profile, int app_index, const StringOrdinal& app_launch_ordinal);
+    Profile* profile, int app_index,
+    const syncer::StringOrdinal& app_launch_ordinal);
 
 // Copy the page and app launch ordinal value for the application at the given
 // index on |profile_source| to |profile_destination|.
diff --git a/chrome/browser/sync/test/integration/sync_app_helper.cc b/chrome/browser/sync/test/integration/sync_app_helper.cc
index 256c1ac..678ef8a 100644
--- a/chrome/browser/sync/test/integration/sync_app_helper.cc
+++ b/chrome/browser/sync/test/integration/sync_app_helper.cc
@@ -5,13 +5,12 @@
 #include "chrome/browser/sync/test/integration/sync_app_helper.h"
 
 #include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/extension_sorting.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/test/integration/extensions_helper.h"
 #include "chrome/browser/sync/test/integration/sync_datatype_helper.h"
 #include "chrome/browser/sync/test/integration/sync_extension_helper.h"
-#include "chrome/common/string_ordinal.h"
 
 namespace {
 
@@ -21,8 +20,8 @@ struct AppState {
   bool IsValid() const;
   bool Equals(const AppState& other) const;
 
-  StringOrdinal app_launch_ordinal;
-  StringOrdinal page_ordinal;
+  syncer::StringOrdinal app_launch_ordinal;
+  syncer::StringOrdinal page_ordinal;
 };
 
 typedef std::map<std::string, AppState> AppStateMap;
@@ -36,8 +35,8 @@ bool AppState::IsValid() const {
 }
 
 bool AppState::Equals(const AppState& other) const {
-  return app_launch_ordinal.Equal(other.app_launch_ordinal) &&
-      page_ordinal.Equal(other.page_ordinal);
+  return app_launch_ordinal.Equals(other.app_launch_ordinal) &&
+      page_ordinal.Equals(other.page_ordinal);
 }
 
 // Load all the app specific values for |id| into |app_state|.
@@ -142,20 +141,22 @@ bool SyncAppHelper::AppStatesMatch(Profile* profile1, Profile* profile2) {
   return true;
 }
 
-StringOrdinal SyncAppHelper::GetPageOrdinalForApp(Profile* profile,
-                                                  const std::string& name) {
+syncer::StringOrdinal SyncAppHelper::GetPageOrdinalForApp(
+    Profile* profile,
+    const std::string& name) {
   return profile->GetExtensionService()->extension_prefs()->
       extension_sorting()->GetPageOrdinal(SyncExtensionHelper::NameToId(name));
 }
 
-void SyncAppHelper::SetPageOrdinalForApp(Profile* profile,
-                                         const std::string& name,
-                                         const StringOrdinal& page_ordinal) {
+void SyncAppHelper::SetPageOrdinalForApp(
+    Profile* profile,
+    const std::string& name,
+    const syncer::StringOrdinal& page_ordinal) {
   profile->GetExtensionService()->extension_prefs()->extension_sorting()->
       SetPageOrdinal(SyncExtensionHelper::NameToId(name), page_ordinal);
 }
 
-StringOrdinal SyncAppHelper::GetAppLaunchOrdinalForApp(
+syncer::StringOrdinal SyncAppHelper::GetAppLaunchOrdinalForApp(
     Profile* profile,
     const std::string& name) {
   return profile->GetExtensionService()->extension_prefs()->
@@ -166,7 +167,7 @@ StringOrdinal SyncAppHelper::GetAppLaunchOrdinalForApp(
 void SyncAppHelper::SetAppLaunchOrdinalForApp(
     Profile* profile,
     const std::string& name,
-    const StringOrdinal& app_launch_ordinal) {
+    const syncer::StringOrdinal& app_launch_ordinal) {
   profile->GetExtensionService()->extension_prefs()->extension_sorting()->
       SetAppLaunchOrdinal(SyncExtensionHelper::NameToId(name),
                           app_launch_ordinal);
diff --git a/chrome/browser/sync/test/integration/sync_app_helper.h b/chrome/browser/sync/test/integration/sync_app_helper.h
index e76bd89..05398a5 100644
--- a/chrome/browser/sync/test/integration/sync_app_helper.h
+++ b/chrome/browser/sync/test/integration/sync_app_helper.h
@@ -9,9 +9,9 @@
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
+#include "sync/api/string_ordinal.h"
 
 class Profile;
-class StringOrdinal;
 class SyncTest;
 
 class SyncAppHelper {
@@ -28,24 +28,26 @@ class SyncAppHelper {
   bool AppStatesMatch(Profile* profile1, Profile* profile2);
 
   // Gets the page ordinal value for the applications with |name| in |profile|.
-  StringOrdinal GetPageOrdinalForApp(Profile* profile, const std::string& name);
+  syncer::StringOrdinal GetPageOrdinalForApp(Profile* profile,
+                                             const std::string& name);
 
   // Sets a new |page_ordinal| value for the application with |name| in
   // |profile|.
   void SetPageOrdinalForApp(Profile* profile,
                             const std::string& name,
-                            const StringOrdinal& page_ordinal);
+                            const syncer::StringOrdinal& page_ordinal);
 
   // Gets the app launch ordinal value for the application with |name| in
   // |profile|.
-  StringOrdinal GetAppLaunchOrdinalForApp(Profile* profile,
-                                          const std::string& name);
+  syncer::StringOrdinal GetAppLaunchOrdinalForApp(Profile* profile,
+                                                  const std::string& name);
 
   // Sets a new |app_launch_ordinal| value for the application with |name| in
   // |profile|.
-  void SetAppLaunchOrdinalForApp(Profile* profile,
-                                 const std::string& name,
-                                 const StringOrdinal& app_launch_ordinal);
+  void SetAppLaunchOrdinalForApp(
+      Profile* profile,
+      const std::string& name,
+      const syncer::StringOrdinal& app_launch_ordinal);
 
   // Fix any NTP icon collisions that are currently in |profile|.
   void FixNTPOrdinalCollisions(Profile* profile);
diff --git a/chrome/browser/sync/test/integration/sync_extension_helper.cc b/chrome/browser/sync/test/integration/sync_extension_helper.cc
index b4c0f1d..0b05557 100644
--- a/chrome/browser/sync/test/integration/sync_extension_helper.cc
+++ b/chrome/browser/sync/test/integration/sync_extension_helper.cc
@@ -13,11 +13,11 @@
 #include "chrome/browser/extensions/pending_extension_info.h"
 #include "chrome/browser/extensions/pending_extension_manager.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/sync/test/integration/sync_datatype_helper.h"
+#include "chrome/browser/sync/test/integration/sync_test.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
-#include "chrome/common/string_ordinal.h"
-#include "chrome/browser/sync/test/integration/sync_test.h"
-#include "chrome/browser/sync/test/integration/sync_datatype_helper.h"
+#include "sync/api/string_ordinal.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using extensions::Extension;
@@ -71,7 +71,7 @@ std::string SyncExtensionHelper::InstallExtension(
     return "";
   }
   profile->GetExtensionService()->OnExtensionInstalled(
-      extension, extension->UpdatesFromGallery(), StringOrdinal());
+      extension, extension->UpdatesFromGallery(), syncer::StringOrdinal());
   return extension->id();
 }
 
diff --git a/chrome/browser/sync/test/integration/two_client_apps_sync_test.cc b/chrome/browser/sync/test/integration/two_client_apps_sync_test.cc
index d12cdd8..d20443b 100644
--- a/chrome/browser/sync/test/integration/two_client_apps_sync_test.cc
+++ b/chrome/browser/sync/test/integration/two_client_apps_sync_test.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/sync/test/integration/sync_app_helper.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
 #include "chrome/common/extensions/extension_constants.h"
+#include "sync/api/string_ordinal.h"
 
 using apps_helper::AllProfilesHaveSameAppsAsVerifier;
 using apps_helper::CopyNTPOrdinals;
@@ -337,14 +338,15 @@ IN_PROC_BROWSER_TEST_F(TwoClientAppsSyncTest, UpdatePageOrdinal) {
   ASSERT_TRUE(SetupSync());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
-  StringOrdinal initial_page = StringOrdinal::CreateInitialOrdinal();
+  syncer::StringOrdinal initial_page =
+      syncer::StringOrdinal::CreateInitialOrdinal();
   InstallApp(GetProfile(0), 0);
   InstallApp(GetProfile(1), 0);
   InstallApp(verifier(), 0);
   ASSERT_TRUE(AwaitQuiescence());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
-  StringOrdinal second_page = initial_page.CreateAfter();
+  syncer::StringOrdinal second_page = initial_page.CreateAfter();
   SetPageOrdinalForApp(GetProfile(0), 0, second_page);
   SetPageOrdinalForApp(verifier(), 0, second_page);
   ASSERT_TRUE(AwaitQuiescence());
@@ -358,14 +360,15 @@ IN_PROC_BROWSER_TEST_F(TwoClientAppsSyncTest, UpdateAppLaunchOrdinal) {
   ASSERT_TRUE(SetupSync());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
-  StringOrdinal initial_position = StringOrdinal::CreateInitialOrdinal();
+  syncer::StringOrdinal initial_position =
+      syncer::StringOrdinal::CreateInitialOrdinal();
   InstallApp(GetProfile(0), 0);
   InstallApp(GetProfile(1), 0);
   InstallApp(verifier(), 0);
   ASSERT_TRUE(AwaitQuiescence());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
-  StringOrdinal second_position = initial_position.CreateAfter();
+  syncer::StringOrdinal second_position = initial_position.CreateAfter();
   SetAppLaunchOrdinalForApp(GetProfile(0), 0, second_position);
   SetAppLaunchOrdinalForApp(verifier(), 0, second_position);
   ASSERT_TRUE(AwaitQuiescence());
@@ -380,7 +383,8 @@ IN_PROC_BROWSER_TEST_F(TwoClientAppsSyncTest, UpdateCWSOrdinals) {
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
   // Change the app launch ordinal.
-  StringOrdinal cws_app_launch_ordinal = GetProfile(0)->GetExtensionService()->
+  syncer::StringOrdinal cws_app_launch_ordinal =
+      GetProfile(0)->GetExtensionService()->
       extension_prefs()->extension_sorting()->GetAppLaunchOrdinal(
           extension_misc::kWebStoreAppId);
   GetProfile(0)->GetExtensionService()->extension_prefs()->extension_sorting()->
@@ -393,7 +397,8 @@ IN_PROC_BROWSER_TEST_F(TwoClientAppsSyncTest, UpdateCWSOrdinals) {
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
   // Change the page ordinal.
-  StringOrdinal cws_page_ordinal = GetProfile(1)->GetExtensionService()->
+  syncer::StringOrdinal cws_page_ordinal =
+      GetProfile(1)->GetExtensionService()->
       extension_prefs()->extension_sorting()->GetPageOrdinal(
           extension_misc::kWebStoreAppId);
   GetProfile(1)->GetExtensionService()->extension_prefs()->
diff --git a/chrome/browser/ui/panels/base_panel_browser_test.cc b/chrome/browser/ui/panels/base_panel_browser_test.cc
index d127f7b..ca20fc4 100644
--- a/chrome/browser/ui/panels/base_panel_browser_test.cc
+++ b/chrome/browser/ui/panels/base_panel_browser_test.cc
@@ -24,11 +24,11 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
-#include "chrome/common/string_ordinal.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/test/web_contents_tester.h"
+#include "sync/api/string_ordinal.h"
 
 #if defined(OS_LINUX)
 #include "chrome/browser/ui/browser_window.h"
@@ -430,7 +430,7 @@ scoped_refptr<Extension> BasePanelBrowserTest::CreateExtension(
   EXPECT_TRUE(extension.get());
   EXPECT_STREQ("", error.c_str());
   browser()->profile()->GetExtensionService()->
-      OnExtensionInstalled(extension.get(), false, StringOrdinal());
+      OnExtensionInstalled(extension.get(), false, syncer::StringOrdinal());
   return extension;
 }
 
diff --git a/chrome/browser/ui/panels/old_base_panel_browser_test.cc b/chrome/browser/ui/panels/old_base_panel_browser_test.cc
index a2b6501b..90923648 100644
--- a/chrome/browser/ui/panels/old_base_panel_browser_test.cc
+++ b/chrome/browser/ui/panels/old_base_panel_browser_test.cc
@@ -27,11 +27,11 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
-#include "chrome/common/string_ordinal.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/test/web_contents_tester.h"
+#include "sync/api/string_ordinal.h"
 
 #if defined(OS_LINUX)
 #include "ui/base/x/x11_util.h"
@@ -446,7 +446,7 @@ scoped_refptr<Extension> OldBasePanelBrowserTest::CreateExtension(
   EXPECT_TRUE(extension.get());
   EXPECT_STREQ("", error.c_str());
   browser()->profile()->GetExtensionService()->
-      OnExtensionInstalled(extension.get(), false, StringOrdinal());
+      OnExtensionInstalled(extension.get(), false, syncer::StringOrdinal());
   return extension;
 }
 
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
index 75cda30..2089aa7 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
@@ -165,7 +165,7 @@ void AppLauncherHandler::CreateAppInfo(
     value->Set("notification", SerializeNotification(*notification));
 
   ExtensionSorting* sorting = prefs->extension_sorting();
-  StringOrdinal page_ordinal = sorting->GetPageOrdinal(extension->id());
+  syncer::StringOrdinal page_ordinal = sorting->GetPageOrdinal(extension->id());
   if (!page_ordinal.IsValid()) {
     // Make sure every app has a page ordinal (some predate the page ordinal).
     // The webstore app should be on the first page.
@@ -177,7 +177,7 @@ void AppLauncherHandler::CreateAppInfo(
   value->SetInteger("page_index",
       sorting->PageStringOrdinalAsInteger(page_ordinal));
 
-  StringOrdinal app_launch_ordinal =
+  syncer::StringOrdinal app_launch_ordinal =
       sorting->GetAppLaunchOrdinal(extension->id());
   if (!app_launch_ordinal.IsValid()) {
     // Make sure every app has a launch ordinal (some predate the launch
@@ -188,7 +188,7 @@ void AppLauncherHandler::CreateAppInfo(
         sorting->CreateNextAppLaunchOrdinal(page_ordinal);
     sorting->SetAppLaunchOrdinal(extension->id(), app_launch_ordinal);
   }
-  value->SetString("app_launch_ordinal", app_launch_ordinal.ToString());
+  value->SetString("app_launch_ordinal", app_launch_ordinal.ToInternalValue());
 }
 
 void AppLauncherHandler::RegisterMessages() {
@@ -652,7 +652,7 @@ void AppLauncherHandler::HandleSetPageIndex(const ListValue* args) {
   double page_index;
   CHECK(args->GetString(0, &extension_id));
   CHECK(args->GetDouble(1, &page_index));
-  const StringOrdinal& page_ordinal =
+  const syncer::StringOrdinal& page_ordinal =
       extension_sorting->PageIntegerAsStringOrdinal(
           static_cast<size_t>(page_index));
 
@@ -687,7 +687,7 @@ void AppLauncherHandler::HandleGenerateAppForLink(const ListValue* args) {
   CHECK(args->GetDouble(2, &page_index));
   ExtensionSorting* extension_sorting =
       extension_service_->extension_prefs()->extension_sorting();
-  const StringOrdinal& page_ordinal =
+  const syncer::StringOrdinal& page_ordinal =
       extension_sorting->PageIntegerAsStringOrdinal(
           static_cast<size_t>(page_index));
 
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.h b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
index d06b48a..93fee067 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.h
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
@@ -15,10 +15,10 @@
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_constants.h"
-#include "chrome/common/string_ordinal.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_ui_message_handler.h"
+#include "sync/api/string_ordinal.h"
 
 class ExtensionService;
 class PrefChangeRegistrar;
@@ -115,7 +115,7 @@ class AppLauncherHandler : public content::WebUIMessageHandler,
     bool is_bookmark_app;
     string16 title;
     GURL app_url;
-    StringOrdinal page_ordinal;
+    syncer::StringOrdinal page_ordinal;
   };
 
   // Reset some instance flags we use to track the currently uninstalling app.