Start ARC and sign in after Chrome OS login

chrome/browser/ui/app_list/arc/arc_app_utils.cc

Index: chrome/browser/ui/app_list/arc/arc_app_utils.cc
diff --git a/chrome/browser/ui/app_list/arc/arc_app_utils.cc b/chrome/browser/ui/app_list/arc/arc_app_utils.cc
index 188178440bb0e7a94ab85d7a1372dab6a179beff..ae889a345ad4a5351c1ee046630247e7425beae4 100644
--- a/chrome/browser/ui/app_list/arc/arc_app_utils.cc
+++ b/chrome/browser/ui/app_list/arc/arc_app_utils.cc
@@ -269,7 +269,11 @@ bool LaunchApp(content::BrowserContext* context,
     DCHECK(arc_session_manager);
 
     bool arc_activated = false;
-    if (!arc_session_manager->IsArcPlayStoreEnabled()) {
+    if (arc_session_manager->IsPersistentArc()) {

[hidehiko, 2017/02/23 10:29:16]

If Play Store is not yet enabled, I think it is still needed to enable it even
under PARC, otherwise apps on Play Store cannot be launched.
That means, apps need to be categorized into two groups, ones can run with PARC,
and ones need Play Store. Am I correct? If so any comments and/or plans?

[hidehiko, 2017/02/23 10:29:16]

nit: Could you elide the brace?

[victorhsieh, 2017/02/24 00:45:00]

Right.  There won't be apps from Play Store in opt-out mode, but default apps
like the note taking one is the exception that conceptually linked to Play
Store.  Clicking on them should launch the opt-in flow just like the opt out
case today.  This should be already the case and pARC shouldn't change that from
user's perspective.

Consider the use cases (line number based on the original copy):
1) launching app in the system image (L267 false -> L313)
2) launching default apps that needs to be installed from Play Store (L267 true
-> L272 -> L278 -> L294)

Now it seems to me that there is no difference between pARC and today here.  I'm
removing my change here, but please let me know if I missed something.

[victorhsieh, 2017/02/25 00:21:33]

Seems like there is an unlikely edge case when apps are registered, but the
instance is not ready.  Modify to bypass the NOTREACHED for pARC.

+      arc_activated = true;
+    }
+
+    if (!arc_activated && !arc_session_manager->IsArcPlayStoreEnabled()) {
       if (!prefs->IsDefault(app_id)) {
         NOTREACHED();
         return false;