Disallow setting VPNs in C++ for child accounts

Bug: 933768
Change-Id: I8778058205a5e6f6f5973cb2831292c7da985329
Reviewed-on: https://chromium-review.googlesource.com/c/1479730Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: Julia Feitosa <carvalheira@google.com>
Cr-Commit-Position: refs/heads/master@{#635092}

chrome/browser/ui/webui/settings/chromeos/internet_handler.cc

@@ -145,8 +145,9 @@ void InternetHandler::AddThirdPartyVpn(const base::ListValue* args) {
     NET_LOG(ERROR) << "Empty app id for " << kAddThirdPartyVpnMessage;
     return;
   }
-  if (profile_ != GetProfileForPrimaryUser()) {
-    NET_LOG(ERROR) << "Only the primary user can add VPNs";
+  if (profile_ != GetProfileForPrimaryUser() || profile_->IsChild()) {
+    NET_LOG(ERROR)
+        << "Only the primary user and non-child accounts can add VPNs";
     return;
   }