[Sync] Move sync's ModelSafeWorker implementations to engine/.

components/sync/driver/glue/ui_model_worker.cc

Index: components/sync/driver/glue/ui_model_worker.cc
diff --git a/components/sync/driver/glue/ui_model_worker.cc b/components/sync/driver/glue/ui_model_worker.cc
deleted file mode 100644
index c812f9a9b54ed6b95cf0c974a3d07f778f2eac48..0000000000000000000000000000000000000000
--- a/components/sync/driver/glue/ui_model_worker.cc
+++ /dev/null
@@ -1,71 +0,0 @@
-// 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 <utility>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/callback.h"
-#include "base/synchronization/waitable_event.h"
-#include "components/sync/base/scoped_event_signal.h"
-
-namespace syncer {
-
-namespace {
-
-void CallDoWorkAndSignalEvent(const WorkCallback& work,
-                              syncer::ScopedEventSignal scoped_event_signal,
-                              SyncerError* error_info) {
-  *error_info = work.Run();
-  // The event in |scoped_event_signal| is signaled at the end of this scope.
-}
-
-}  // namespace
-
-UIModelWorker::UIModelWorker(
-    scoped_refptr<base::SingleThreadTaskRunner> ui_thread)
-    : ui_thread_(std::move(ui_thread)) {}
-
-SyncerError UIModelWorker::DoWorkAndWaitUntilDoneImpl(
-    const WorkCallback& work) {
-  SyncerError error_info;
-  if (ui_thread_->BelongsToCurrentThread()) {
-    DLOG(WARNING) << "DoWorkAndWaitUntilDone called from "
-                  << "ui_loop_. Probably a nested invocation?";
-    return work.Run();
-  }
-
-  // Signaled when the task is deleted, i.e. after it runs or when it is
-  // abandoned.
-  base::WaitableEvent work_done_or_abandoned(
-      base::WaitableEvent::ResetPolicy::AUTOMATIC,
-      base::WaitableEvent::InitialState::NOT_SIGNALED);
-
-  if (!ui_thread_->PostTask(FROM_HERE,
-                            base::Bind(&CallDoWorkAndSignalEvent, work,
-                                       base::Passed(syncer::ScopedEventSignal(
-                                           &work_done_or_abandoned)),
-                                       &error_info))) {
-    DLOG(WARNING) << "Could not post work to UI loop.";
-    error_info = CANNOT_DO_WORK;
-    return error_info;
-  }
-  work_done_or_abandoned.Wait();
-
-  return error_info;
-}
-
-ModelSafeGroup UIModelWorker::GetModelSafeGroup() {
-  return GROUP_UI;
-}
-
-bool UIModelWorker::IsOnModelThread() {
-  return ui_thread_->BelongsToCurrentThread();
-}
-
-UIModelWorker::~UIModelWorker() {}
-
-}  // namespace syncer