mash: Update shelf pin prefs in ShelfModelObserver overrides.

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

Index: chrome/browser/ui/ash/launcher/launcher_arc_app_updater.cc
diff --git a/chrome/browser/ui/ash/launcher/launcher_arc_app_updater.cc b/chrome/browser/ui/ash/launcher/launcher_arc_app_updater.cc
index 503d9101224d48a1e92cbeeaa122e9b86b5a69cf..ac6ac97d70ea6495566ea9fb2ade5a4baac7c435 100644
--- a/chrome/browser/ui/ash/launcher/launcher_arc_app_updater.cc
+++ b/chrome/browser/ui/ash/launcher/launcher_arc_app_updater.cc
@@ -26,6 +26,13 @@ void LauncherArcAppUpdater::OnAppRegistered(
 }
 
 void LauncherArcAppUpdater::OnAppRemoved(const std::string& app_id) {
+  // When disabling ARC, apps are removed, but sync items should not be deleted.

[James Cook, 2017/03/29 14:28:02]

I suggest explaining why the items should not be deleted, like it your CL
comments.

[msw, 2017/03/29 21:34:17]

Done.

+  // Notify the delegate that the app is being disabled, and shelf item removal
+  // should not trigger pin position removal from the sync model. When app
+  // removal should be synced, AppListModelBuilder::RemoveApp will call
+  // AppListSyncableService::RemoveUninstalledItem and trigger RemoveSyncItem.
+  delegate()->OnAppDisabling(app_id);
   delegate()->OnAppUninstalledPrepared(browser_context(), app_id);
   delegate()->OnAppUninstalled(browser_context(), app_id);
+  delegate()->OnAppDisabled(app_id);

[James Cook, 2017/03/29 14:28:03]

It seems like these OnAppDisabling() etc. functions should also be called from
LauncherExtensionAppUpdater, or these shouldn't be delegate methods and
LauncherArcAppUpdater should be calling directly into CLC.

[msw, 2017/03/29 21:34:17]

Good call! Changed this to directly call into ChromeLauncherController.

 }