Introduce the plumbing necessary to report Unrecoverable error from model safe workers.

chrome/browser/sync/js/js_sync_manager_observer.cc

Index: chrome/browser/sync/js/js_sync_manager_observer.cc
diff --git a/chrome/browser/sync/js/js_sync_manager_observer.cc b/chrome/browser/sync/js/js_sync_manager_observer.cc
index 7714f27422a7bc145920411c0620b84d0015e571..a62f66b104fb0512dfdfb30f07a744be02f9f1b6 100644
--- a/chrome/browser/sync/js/js_sync_manager_observer.cc
+++ b/chrome/browser/sync/js/js_sync_manager_observer.cc
@@ -134,6 +134,19 @@ void JsSyncManagerObserver::OnClearServerDataFailed() {
   HandleJsEvent(FROM_HERE, "onClearServerDataFailed", JsEventDetails());
 }
 
+void JsSyncManagerObserver::OnUnrecoverableError(
+    const tracked_objects::Location& location,
+    const std::string& message) {
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.SetString("location", location.ToString());
+  details.SetString("message", message);
+  HandleJsEvent(FROM_HERE, "onUnrecoverableError", JsEventDetails(&details));
+}
+
+
 void JsSyncManagerObserver::HandleJsEvent(
     const tracked_objects::Location& from_here,
     const std::string& name, const JsEventDetails& details) {