Use the location where FileDescriptorWatcher is created to track the libevent handlers

base/message_loop/message_pump_libevent_unittest.cc

Index: base/message_loop/message_pump_libevent_unittest.cc
diff --git a/base/message_loop/message_pump_libevent_unittest.cc b/base/message_loop/message_pump_libevent_unittest.cc
index a23b3543f3d25ade396ae62334a2d3c19b214920..3e7a200a2352a9a9ea37a6347f84b95781a2bbce 100644
--- a/base/message_loop/message_pump_libevent_unittest.cc
+++ b/base/message_loop/message_pump_libevent_unittest.cc
@@ -88,7 +88,7 @@ class StupidWatcher : public MessagePumpLibevent::Watcher {
 #define MAYBE_TestWatchingFromBadThread TestWatchingFromBadThread
 #endif
 TEST_F(MessagePumpLibeventTest, MAYBE_TestWatchingFromBadThread) {
-  MessagePumpLibevent::FileDescriptorWatcher watcher;
+  MessagePumpLibevent::FileDescriptorWatcher watcher(FROM_HERE);
   StupidWatcher delegate;
 
   ASSERT_DCHECK_DEATH(
@@ -137,7 +137,7 @@ class DeleteWatcher : public BaseWatcher {
 TEST_F(MessagePumpLibeventTest, DeleteWatcher) {
   std::unique_ptr<MessagePumpLibevent> pump(new MessagePumpLibevent);
   MessagePumpLibevent::FileDescriptorWatcher* watcher =
-      new MessagePumpLibevent::FileDescriptorWatcher;
+      new MessagePumpLibevent::FileDescriptorWatcher(FROM_HERE);
   DeleteWatcher delegate(watcher);
   pump->WatchFileDescriptor(pipefds_[1],
       false, MessagePumpLibevent::WATCH_READ_WRITE, watcher, &delegate);
@@ -161,7 +161,7 @@ class StopWatcher : public BaseWatcher {
 
 TEST_F(MessagePumpLibeventTest, StopWatcher) {
   std::unique_ptr<MessagePumpLibevent> pump(new MessagePumpLibevent);
-  MessagePumpLibevent::FileDescriptorWatcher watcher;
+  MessagePumpLibevent::FileDescriptorWatcher watcher(FROM_HERE);
   StopWatcher delegate(&watcher);
   pump->WatchFileDescriptor(pipefds_[1],
       false, MessagePumpLibevent::WATCH_READ_WRITE, &watcher, &delegate);
@@ -196,7 +196,7 @@ class NestedPumpWatcher : public MessagePumpLibevent::Watcher {
 
 TEST_F(MessagePumpLibeventTest, NestedPumpWatcher) {
   std::unique_ptr<MessagePumpLibevent> pump(new MessagePumpLibevent);
-  MessagePumpLibevent::FileDescriptorWatcher watcher;
+  MessagePumpLibevent::FileDescriptorWatcher watcher(FROM_HERE);
   NestedPumpWatcher delegate;
   pump->WatchFileDescriptor(pipefds_[1],
       false, MessagePumpLibevent::WATCH_READ, &watcher, &delegate);
@@ -244,7 +244,7 @@ TEST_F(MessagePumpLibeventTest, QuitWatcher) {
   MessagePumpLibevent* pump = new MessagePumpLibevent;  // owned by |loop|.
   MessageLoop loop(WrapUnique(pump));
   RunLoop run_loop;
-  MessagePumpLibevent::FileDescriptorWatcher controller;
+  MessagePumpLibevent::FileDescriptorWatcher controller(FROM_HERE);
   QuitWatcher delegate(&controller, &run_loop);
   WaitableEvent event(WaitableEvent::ResetPolicy::AUTOMATIC,
                       WaitableEvent::InitialState::NOT_SIGNALED);