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

chrome/browser/sync/glue/browser_thread_model_worker.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/browser_thread_model_worker.h"
 
 #include "base/synchronization/waitable_event.h"
 #include "content/browser/browser_thread.h"
 
 using base::WaitableEvent;
 
 namespace browser_sync {
 
 BrowserThreadModelWorker::BrowserThreadModelWorker(
     BrowserThread::ID thread, ModelSafeGroup group)
     : thread_(thread), group_(group) {}
 
 BrowserThreadModelWorker::~BrowserThreadModelWorker() {}
 
-void BrowserThreadModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
+UnrecoverableErrorInfo BrowserThreadModelWorker::DoWorkAndWaitUntilDone(
+    const WorkCallback& work) {
+  UnrecoverableErrorInfo error_info;
   if (BrowserThread::CurrentlyOn(thread_)) {
     DLOG(WARNING) << "Already on thread " << thread_;
-    work->Run();
-    return;
+    return work.Run();
   }
   WaitableEvent done(false, false);
   if (!BrowserThread::PostTask(
       thread_,
       FROM_HERE,
       NewRunnableMethod(
           this,
           &BrowserThreadModelWorker::CallDoWorkAndSignalTask,
           work,
-          &done))) {
+          &done,
+          &error_info))) {
     NOTREACHED() << "Failed to post task to thread " << thread_;
-    return;
+    return error_info;
   }
   done.Wait();
+  return error_info;
 }
 
 void BrowserThreadModelWorker::CallDoWorkAndSignalTask(
-    Callback0::Type* work, WaitableEvent* done) {
+    const WorkCallback& work,
+    WaitableEvent* done,
+    UnrecoverableErrorInfo* error_info) {
   DCHECK(BrowserThread::CurrentlyOn(thread_));
-  work->Run();
+  *error_info = work.Run();
   done->Signal();
 }
 
 ModelSafeGroup BrowserThreadModelWorker::GetModelSafeGroup() {
   return group_;
 }
 
 DatabaseModelWorker::DatabaseModelWorker()
     : BrowserThreadModelWorker(BrowserThread::DB, GROUP_DB) {}
 
 DatabaseModelWorker::~DatabaseModelWorker() {}
 
 void DatabaseModelWorker::CallDoWorkAndSignalTask(
-    Callback0::Type* work, WaitableEvent* done) {
-  BrowserThreadModelWorker::CallDoWorkAndSignalTask(work, done);
+    const WorkCallback& work,
+    WaitableEvent* done,
+    UnrecoverableErrorInfo* error_info) {
+  BrowserThreadModelWorker::CallDoWorkAndSignalTask(work, done, error_info);
 }
 
 FileModelWorker::FileModelWorker()
     : BrowserThreadModelWorker(BrowserThread::FILE, GROUP_FILE) {}
 
 FileModelWorker::~FileModelWorker() {}
 
 void FileModelWorker::CallDoWorkAndSignalTask(
-    Callback0::Type* work, WaitableEvent* done) {
-  BrowserThreadModelWorker::CallDoWorkAndSignalTask(work, done);
+    const WorkCallback& work,
+    WaitableEvent* done,
+    UnrecoverableErrorInfo* error_info) {
+  BrowserThreadModelWorker::CallDoWorkAndSignalTask(work, done, error_info);
 }
 
 }  // namespace browser_sync