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

chrome/browser/sync/glue/password_model_worker.cc

Index: chrome/browser/sync/glue/password_model_worker.cc
diff --git a/chrome/browser/sync/glue/password_model_worker.cc b/chrome/browser/sync/glue/password_model_worker.cc
index 1b4ad83f9bb8f478ed90824711b261c7a0f48fab..2d0d7038a617350d345b3178f652158822f50daa 100644
--- a/chrome/browser/sync/glue/password_model_worker.cc
+++ b/chrome/browser/sync/glue/password_model_worker.cc
@@ -13,6 +13,7 @@
 using base::WaitableEvent;
 
 namespace browser_sync {
+using sessions::UnrecoverableErrorInfo;
 
 PasswordModelWorker::PasswordModelWorker(PasswordStore* password_store)
   : password_store_(password_store) {
@@ -21,17 +22,22 @@ PasswordModelWorker::PasswordModelWorker(PasswordStore* password_store)
 
 PasswordModelWorker::~PasswordModelWorker() {}
 
-void PasswordModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
+UnrecoverableErrorInfo PasswordModelWorker::DoWorkAndWaitUntilDone(
+    const WorkCallback& work) {
   WaitableEvent done(false, false);
+  UnrecoverableErrorInfo error_info;
   password_store_->ScheduleTask(
       NewRunnableMethod(this, &PasswordModelWorker::CallDoWorkAndSignalTask,
-                        work, &done));
+                        work, &done, &error_info));
   done.Wait();
+  return error_info;
 }
 
-void PasswordModelWorker::CallDoWorkAndSignalTask(Callback0::Type* work,
-                                                  WaitableEvent* done) {
-  work->Run();
+void PasswordModelWorker::CallDoWorkAndSignalTask(
+    const WorkCallback& work,
+    WaitableEvent* done,
+    UnrecoverableErrorInfo* error_info) {
+  *error_info = work.Run();
   done->Signal();
 }