Remove ModelSafeWorker::work_done_or_stopped().

components/sync/engine/signal_event_on_delete.cc

Index: components/sync/engine/signal_event_on_delete.cc
diff --git a/components/sync/engine/signal_event_on_delete.cc b/components/sync/engine/signal_event_on_delete.cc
new file mode 100644
index 0000000000000000000000000000000000000000..82b61680c0e3c277a9a4d43c63bd45081b631895
--- /dev/null
+++ b/components/sync/engine/signal_event_on_delete.cc
@@ -0,0 +1,36 @@
+// Copyright 2016 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/engine/signal_event_on_delete.h"
+
+#include "base/logging.h"
+#include "base/synchronization/waitable_event.h"
+
+namespace syncer {
+
+SignalEventOnDelete::SignalEventOnDelete(base::WaitableEvent* event)

[Nicolas Zea, 2016/11/01 22:39:23]

Although this is all pretty basic logic, would be good to have a few simple unit
tests (which are also a useful reference for how to use this kind of object). 

[fdoray, 2016/11/02 15:52:05]

Done.

+    : event_(event) {
+  DCHECK(event_);
+}
+
+SignalEventOnDelete::SignalEventOnDelete(SignalEventOnDelete&& other)
+    : event_(other.event_) {
+  other.event_ = nullptr;
+}
+
+SignalEventOnDelete& SignalEventOnDelete::operator=(
+    SignalEventOnDelete&& other) {
+  DCHECK(!event_);
+  event_ = other.event_;
+  other.event_ = nullptr;
+  return *this;
+}
+
+SignalEventOnDelete::~SignalEventOnDelete() {
+  if (event_) {
+    event_->Signal();
+  }
+}
+
+}  // namespace syncer