Add gservices flag for configuring the URL vending redirects to when TOS is inaccessible due to no/bad network.

core/java/android/provider/Settings.java

@@ -2916,6 +2916,13 @@ public final class Settings {
          */
         public static final String VENDING_TOS_URL = "vending_tos_url";
 
+        /**
+         * URL to navigate to in browser (not Market) when the terms of service
+         * for Vending Machine could not be accessed due to bad network
+         * connection.
+         */
+        public static final String VENDING_TOS_MISSING_URL = "vending_tos_missing_url";
+
         /**
          * Whether to use sierraqa instead of sierra tokens for the purchase flow in
          * Vending Machine.