arc: Support pinned apps across Arc-enabled and Arc-disabled platforms.

chrome/browser/ui/app_list/app_list_syncable_service.cc

Index: chrome/browser/ui/app_list/app_list_syncable_service.cc
diff --git a/chrome/browser/ui/app_list/app_list_syncable_service.cc b/chrome/browser/ui/app_list/app_list_syncable_service.cc
index 261b361ff62c4902f0e0c1ba9637c7eb2e9b48c0..63bc4fc5d665a6452b956e2eecef98da113837f2 100644
--- a/chrome/browser/ui/app_list/app_list_syncable_service.cc
+++ b/chrome/browser/ui/app_list/app_list_syncable_service.cc
@@ -66,6 +66,7 @@ void UpdateSyncItemFromSync(const sync_pb::AppListSpecifics& specifics,
   item->parent_id = specifics.parent_id();
   if (!specifics.item_ordinal().empty())
     item->item_ordinal = syncer::StringOrdinal(specifics.item_ordinal());
+  item->item_pin_ordinal = syncer::StringOrdinal(specifics.item_pin_ordinal());

[stevenjb, 2016/06/14 22:44:08]

An unfortunate side effect of this is that if an older version of chrome updates
a sync item (e.g. because it was moved) it would inadvertantly unpin the item.

Looking back through the sync code, I think this is what we want for both
item_ordinal and item_pin_ordinal:

if (specifics.has_item_pin_ordinal())
  item->item_pin_ordinal = syncer::StringOrdinal(specifics.item_pin_ordinal());

That way if the value is unset (vs. empty), any existing state will not be
overwritten.

(For item_ordinal those are synonymous since item_ordinal.empty() has no special
meaning, whereas with item_pin_ordinal, empty() means unpinned)

[khmel, 2016/06/15 17:01:19]

That is great point. I missed this possibility, thanks! Also extended unit_tests

 }
 
 bool UpdateSyncItemFromAppItem(const AppListItem* app_item,
@@ -96,8 +97,10 @@ void GetSyncSpecificsFromSyncItem(const AppListSyncableService::SyncItem* item,
   specifics->set_item_type(item->item_type);
   specifics->set_item_name(item->item_name);
   specifics->set_parent_id(item->parent_id);
-  if (item->item_ordinal.IsValid())
-    specifics->set_item_ordinal(item->item_ordinal.ToInternalValue());
+  specifics->set_item_ordinal(item->item_ordinal.IsValid() ?
+      item->item_ordinal.ToInternalValue() : std::string());
+  specifics->set_item_pin_ordinal(item->item_pin_ordinal.IsValid() ?
+      item->item_pin_ordinal.ToInternalValue() : std::string());
 }
 
 syncer::SyncData GetSyncDataFromSyncItem(
@@ -298,6 +301,19 @@ void AppListSyncableService::BuildModel() {
     drive_app_provider_.reset(new DriveAppProvider(profile_, this));
 }
 
+void AppListSyncableService::AddObserverAndStart(Observer* observer) {
+  observer_list_.AddObserver(observer);
+  SyncStarted();
+}
+
+void AppListSyncableService::RemoveObserver(Observer* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
+void AppListSyncableService::NotifyObserversSyncUpdated() {
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnSyncModelUpdated());
+}
+
 size_t AppListSyncableService::GetNumSyncItemsForTest() {
   // If the model isn't built yet, there will be no sync items.
   GetModel();
@@ -422,6 +438,30 @@ AppListSyncableService::CreateSyncItemFromAppItem(AppListItem* app_item) {
   return sync_item;
 }
 
+syncer::StringOrdinal AppListSyncableService::GetPinPosition(
+    const std::string& app_id) {
+  SyncItem* sync_item = FindSyncItem(app_id);
+  if (!sync_item)
+    return syncer::StringOrdinal();
+  return sync_item->item_pin_ordinal;
+}
+
+void AppListSyncableService::SetPinPosition(
+    const std::string& app_id,
+    const syncer::StringOrdinal& item_pin_ordinal) {
+  SyncItem* sync_item = FindSyncItem(app_id);
+  SyncChange::SyncChangeType sync_change_type;
+  if (sync_item) {
+    sync_change_type = SyncChange::ACTION_UPDATE;
+  } else {
+    sync_item = CreateSyncItem(app_id, sync_pb::AppListSpecifics::TYPE_APP);
+    sync_change_type = SyncChange::ACTION_ADD;
+  }
+
+  sync_item->item_pin_ordinal = item_pin_ordinal;
+  SendSyncChange(sync_item, sync_change_type);
+}
+
 void AppListSyncableService::AddOrUpdateFromSyncItem(AppListItem* app_item) {
   // Do not create a sync item for the OEM folder here, do that in
   // ResolveFolderPositions once the position has been resolved.
@@ -668,6 +708,8 @@ syncer::SyncMergeResult AppListSyncableService::MergeDataAndStartSyncing(
   // Start observing app list model changes.
   model_observer_.reset(new ModelObserver(this));
 
+  NotifyObserversSyncUpdated();
+
   return result;
 }
 
@@ -726,6 +768,8 @@ syncer::SyncError AppListSyncableService::ProcessSyncChanges(
   // Continue observing app list model changes.
   model_observer_.reset(new ModelObserver(this));
 
+  NotifyObserversSyncUpdated();
+
   return syncer::SyncError();
 }
 
@@ -834,8 +878,10 @@ void AppListSyncableService::UpdateAppItemFromSyncItem(
     const AppListSyncableService::SyncItem* sync_item,
     AppListItem* app_item) {
   VLOG(2) << this << " UpdateAppItemFromSyncItem: " << sync_item->ToString();
-  if (!app_item->position().Equals(sync_item->item_ordinal))
+  if (sync_item->item_ordinal.IsValid() &&
+      !app_item->position().Equals(sync_item->item_ordinal)) {
     model_->SetItemPosition(app_item, sync_item->item_ordinal);
+  }
   // Only update the item name if it is a Folder or the name is empty.
   if (sync_item->item_name != app_item->name() &&
       sync_item->item_id != kOemFolderId &&
@@ -1013,6 +1059,7 @@ std::string AppListSyncableService::SyncItem::ToString() const {
     res += " [" + item_ordinal.ToDebugString() + "]";
     if (!parent_id.empty())
       res += " <" + parent_id.substr(0, 8) + ">";
+    res += " [" + item_pin_ordinal.ToDebugString() + "]";
   }
   return res;
 }