[Sync] Allow sync start without sign-in if the local sync backend is on.

chrome/browser/ui/sync/sync_promo_ui.cc

Index: chrome/browser/ui/sync/sync_promo_ui.cc
diff --git a/chrome/browser/ui/sync/sync_promo_ui.cc b/chrome/browser/ui/sync/sync_promo_ui.cc
index 3fa574b6483f4358dad9aa04427e099145d549d1..bf9fde37de83e3f71a17874dec4cecfb894c8ffe 100644
--- a/chrome/browser/ui/sync/sync_promo_ui.cc
+++ b/chrome/browser/ui/sync/sync_promo_ui.cc
@@ -13,8 +13,8 @@ bool SyncPromoUI::ShouldShowSyncPromo(Profile* profile) {
     return false;
   }
 
-  // Don't show if sync is not allowed to start.
-  if (!profile->IsSyncAllowed())
+  // Don't show if sync is not allowed to start or is running in local mode.
+  if (!profile->IsSyncAllowed() || profile->IsLocalSyncEnabled())

[Nicolas Zea, 2016/12/15 00:37:28]

See other comment. Is this the only callsite that uses
Profile::IsLocalSyncEnabled? Seems unnecessary to expose that at the profile
level. I wonder if this place should just be checking the pref directly then via
SyncPrefs (same goes for IsSyncAllowed)

[pastarmovj, 2016/12/16 17:04:48]

Yes this is the only site that needs IsLocalSyncEnabled but there are many that
use IsSyncAllowed. I removed my function in favor of direct access to the pref.

     return false;
 
   return true;