[Extensions] Sync the 'allowed scripting on all urls' preference

sync/protocol/extension_specifics.proto

Index: sync/protocol/extension_specifics.proto
diff --git a/sync/protocol/extension_specifics.proto b/sync/protocol/extension_specifics.proto
index 2ef3f25c008843a6caae703e9c5ef312ca5d220b..8e724a31916b367da696b8021c11feab393c0ba8 100644
--- a/sync/protocol/extension_specifics.proto
+++ b/sync/protocol/extension_specifics.proto
@@ -42,5 +42,11 @@ message ExtensionSpecifics {
 
   // Whether this extension was installed by the custodian of a supervised user.
   optional bool installed_by_custodian = 8;
+
+  // Whether this extension has explicit user consent access to all urls.
+  // This is a tri-state boolean, so, unlike most fields here, it really *is*
+  // optional and may be absent. We need this for the time being because we need
+  // to know if a user has not set an explicit preference.
+  optional bool all_urls_enabled = 9;
 }