[Sync] Signal UIModelWorker to abort on sync shutdown.

components/sync/driver/glue/ui_model_worker_unittest.cc

 // Copyright (c) 2012 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 "components/sync/driver/glue/ui_model_worker.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
@@ skipping 21 matching lines @@
   return base::Bind(&DoWork, base::ThreadTaskRunnerHandle::Get(), work);
 }
 
 class SyncUIModelWorkerTest : public testing::Test {
  public:
   SyncUIModelWorkerTest() : sync_thread_("SyncThreadForTest") {
     sync_thread_.Start();
     worker_ = new UIModelWorker(base::ThreadTaskRunnerHandle::Get());
   }
 
-  void PostWorkToSyncThread(WorkCallback work) {
+  void PostWorkToSyncThread(base::Closure work) {
     sync_thread_.task_runner()->PostTask(
         FROM_HERE,
         base::Bind(base::IgnoreResult(&UIModelWorker::DoWorkAndWaitUntilDone),
-                   worker_, work));
+                   worker_, ClosureToWorkCallback(work)));
+  }
+
+  // Work function for ShutdownNoDeadlock below.
+  void DeadlockTest(base::Closure quit_closure) {
+    // Unblock the sync thread.
+    worker_->RequestStop();
+
+    // Join the sync thread.
+    sync_thread_.Stop();
+
+    // Let the test complete.
+    quit_closure.Run();
   }
 
  private:
   base::MessageLoop ui_loop_;
   base::Thread sync_thread_;
   scoped_refptr<UIModelWorker> worker_;
 };
 
 TEST_F(SyncUIModelWorkerTest, ScheduledWorkRunsOnUILoop) {
   base::RunLoop run_loop;
-  PostWorkToSyncThread(ClosureToWorkCallback(run_loop.QuitClosure()));
+  PostWorkToSyncThread(run_loop.QuitClosure());
   // This won't quit until the QuitClosure is run.
   run_loop.Run();
 }
 
+TEST_F(SyncUIModelWorkerTest, ShutdownNoDeadlock) {
+  base::RunLoop run_loop;
+  PostWorkToSyncThread(base::Bind(&SyncUIModelWorkerTest::DeadlockTest,
+                                  base::Unretained(this),
+                                  run_loop.QuitClosure()));
+  run_loop.Run();
+}
+
 }  // namespace
 }  // namespace syncer