Implement local storage for App List in case app sync is off.

chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc

Index: chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc
index 3f2e4bc9e5ce84a0efb1925ae2109400bb203228..9f72b754dc4181708e7dadfeaf3af7fccbb5e530 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl_unittest.cc
@@ -4015,3 +4015,35 @@ TEST_F(ChromeLauncherControllerImplTest, CheckPositionConflict) {
   EXPECT_TRUE(
       position_3.Equals(app_service_->GetPinPosition(extension3_->id())));
 }
+
+// Test the case when sync app is turned off and we need to use local copy to
+// support user's pins.
+TEST_F(ChromeLauncherControllerImplTest, SyncOffLocalUpdate) {
+  InitLauncherController();
+
+  extension_service_->AddExtension(extension1_.get());
+  extension_service_->AddExtension(extension2_.get());
+
+  syncer::SyncChangeList sync_list;
+  InsertAddPinChange(&sync_list, 0, extension_misc::kChromeAppId);
+  InsertAddPinChange(&sync_list, 1, extension1_->id());
+  InsertAddPinChange(&sync_list, 1, extension2_->id());
+  SendPinChanges(sync_list, true);
+
+  EXPECT_EQ("AppList, Chrome, App1, App2", GetPinnedAppStatus());
+
+  syncer::SyncDataList copy_sync_list =
+      app_service_->GetAllSyncData(syncer::APP_LIST);
+
+  app_service_->StopSyncing(syncer::APP_LIST);
+  RecreateChromeLauncher();
+
+  // Pinned state should not change.
+  EXPECT_EQ("AppList, Chrome, App1, App2", GetPinnedAppStatus());
+  launcher_controller_->UnpinAppWithID(extension2_->id());
+  EXPECT_EQ("AppList, Chrome, App1", GetPinnedAppStatus());
+
+  // Resume syncing and sync information overrides local copy.
+  StartAppSyncService(copy_sync_list);
+  EXPECT_EQ("AppList, Chrome, App1, App2", GetPinnedAppStatus());
+}