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

chrome/browser/sync/glue/ui_model_worker.cc

Index: chrome/browser/sync/glue/ui_model_worker.cc
diff --git a/chrome/browser/sync/glue/ui_model_worker.cc b/chrome/browser/sync/glue/ui_model_worker.cc
index 020e3c9645be909901af84cff868fe927595f1b5..5bb3eeebd866759e33e6a647fa56b324e72001a9 100644
--- a/chrome/browser/sync/glue/ui_model_worker.cc
+++ b/chrome/browser/sync/glue/ui_model_worker.cc
@@ -10,8 +10,10 @@
 #include "content/browser/browser_thread.h"
 
 namespace browser_sync {
+using sessions::UnrecoverableErrorInfo;
 
-void UIModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
+UnrecoverableErrorInfo UIModelWorker::DoWorkAndWaitUntilDone(
+    Callback1<sessions::UnrecoverableErrorInfo*>::Type* work) {
   // In most cases, this method is called in WORKING state. It is possible this
   // gets called when we are in the RUNNING_MANUAL_SHUTDOWN_PUMP state, because
   // the UI loop has initiated shutdown but the syncer hasn't got the memo yet.
@@ -19,12 +21,12 @@ void UIModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
   // code handling this case in Stop(). Note there _no_ way we can be in here
   // with state_ = STOPPED, so it is safe to read / compare in this case.
   CHECK_NE(ANNOTATE_UNPROTECTED_READ(state_), STOPPED);
-
+  UnrecoverableErrorInfo error_info;
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     DLOG(WARNING) << "DoWorkAndWaitUntilDone called from "
       << "ui_loop_. Probably a nested invocation?";
-    work->Run();
-    return;
+    work->Run(&error_info);
+    return error_info;
   }
 
   // Create an unsignaled event to wait on.
@@ -35,16 +37,19 @@ void UIModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
     // The task is owned by the message loop as per usual.
     base::AutoLock lock(lock_);
     DCHECK(!pending_work_);
-    pending_work_ = new CallDoWorkAndSignalTask(work, &work_done, this);
+    UnrecoverableErrorInfo error_info;
+    pending_work_ = new CallDoWorkAndSignalTask(work, &work_done, this,
+                                                &error_info);
     if (!BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, pending_work_)) {
       LOG(WARNING) << "Could not post work to UI loop.";
       pending_work_ = NULL;
       syncapi_event_.Signal();
-      return;
+      return error_info;
     }
   }
   syncapi_event_.Signal();  // Notify that the syncapi produced work for us.
   work_done.Wait();
+  return error_info;
 }
 
 UIModelWorker::UIModelWorker()
@@ -110,7 +115,7 @@ void UIModelWorker::CallDoWorkAndSignalTask::Run() {
     // actually gets destroyed.
     return;
   }
-  work_->Run();
+  work_->Run(error_info_);
 
   // Sever ties with work_ to allow the sanity-checking above that we don't
   // get run twice.