Revert 222154 "sync: Gracefully handle very early shutdown"

trunk/src/sync/internal_api/public/base/cancelation_signal.cc

Index: trunk/src/sync/internal_api/public/base/cancelation_signal.cc
===================================================================
--- trunk/src/sync/internal_api/public/base/cancelation_signal.cc	(revision 222204)
+++ trunk/src/sync/internal_api/public/base/cancelation_signal.cc	(working copy)
@@ -1,52 +0,0 @@
-// Copyright 2013 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 "sync/internal_api/public/base/cancelation_signal.h"
-
-#include "base/logging.h"
-#include "sync/internal_api/public/base/cancelation_observer.h"
-
-namespace syncer {
-
-CancelationSignal::CancelationSignal()
-  : stop_requested_(false),
-    handler_(NULL) { }
-
-CancelationSignal::~CancelationSignal() {
-  DCHECK(!handler_);
-}
-
-bool CancelationSignal::TryRegisterHandler(CancelationObserver* handler) {
-  base::AutoLock lock(stop_requested_lock_);
-  DCHECK(!handler_);
-
-  if (stop_requested_)
-    return false;
-
-  handler_ = handler;
-  return true;
-}
-
-void CancelationSignal::UnregisterHandler(CancelationObserver* handler) {
-  base::AutoLock lock(stop_requested_lock_);
-  DCHECK_EQ(handler_, handler);
-  handler_ = NULL;
-}
-
-bool CancelationSignal::IsStopRequested() {
-  base::AutoLock lock(stop_requested_lock_);
-  return stop_requested_;
-}
-
-void CancelationSignal::RequestStop() {
-  base::AutoLock lock(stop_requested_lock_);
-  DCHECK(!stop_requested_);
-
-  stop_requested_ = true;
-  if (handler_) {
-    handler_->OnStopRequested();
-  }
-}
-
-}  // namespace syncer