Update from https://crrev.com/315085

base/win/object_watcher.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 "base/win/object_watcher.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 
 namespace base {
@@ skipping 59 matching lines @@
   }
 
   weak_factory_.InvalidateWeakPtrs();
   object_ = NULL;
   wait_object_ = NULL;
 
   MessageLoop::current()->RemoveDestructionObserver(this);
   return true;
 }
 
-HANDLE ObjectWatcher::GetWatchedObject() {
+bool ObjectWatcher::IsWatching() const {
+  return object_ != NULL;
+}
+
+HANDLE ObjectWatcher::GetWatchedObject() const {
   return object_;
 }
 
 // static
 void CALLBACK ObjectWatcher::DoneWaiting(void* param, BOOLEAN timed_out) {
   DCHECK(!timed_out);
 
   // The destructor blocks on any callbacks that are in flight, so we know that
   // that is always a pointer to a valid ObjectWater.
   ObjectWatcher* that = static_cast<ObjectWatcher*>(param);
@@ skipping 11 matching lines @@
 }
 
 void ObjectWatcher::WillDestroyCurrentMessageLoop() {
   // Need to shutdown the watch so that we don't try to access the MessageLoop
   // after this point.
   StopWatching();
 }
 
 }  // namespace win
 }  // namespace base