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

base/message_loop/message_pump_libevent.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/message_loop/message_pump_libevent.h"
 
 #include <errno.h>
 #include <unistd.h>
 
 #include <memory>
@@ skipping 25 matching lines @@
 //
 // TODO(dkegel):
 // At the moment bad things happen if a FileDescriptorWatcher
 // is active after its MessagePumpLibevent has been destroyed.
 // See MessageLoopTest.FileDescriptorWatcherOutlivesMessageLoop
 // Not clear yet whether that situation occurs in practice,
 // but if it does, we need to fix it.
 
 namespace base {
 
-MessagePumpLibevent::FileDescriptorWatcher::FileDescriptorWatcher()
+MessagePumpLibevent::FileDescriptorWatcher::FileDescriptorWatcher(
+    const tracked_objects::Location& from_here)
     : event_(NULL),
       pump_(NULL),
       watcher_(NULL),
-      was_destroyed_(NULL) {
-}
+      was_destroyed_(NULL),
+      created_from_location_(from_here) {}
 
 MessagePumpLibevent::FileDescriptorWatcher::~FileDescriptorWatcher() {
   if (event_) {
     StopWatchingFileDescriptor();
   }
   if (was_destroyed_) {
     DCHECK(!*was_destroyed_);
     *was_destroyed_ = true;
   }
 }
@@ skipping 246 matching lines @@
   return true;
 }
 
 // static
 void MessagePumpLibevent::OnLibeventNotification(int fd,
                                                  short flags,
                                                  void* context) {
   FileDescriptorWatcher* controller =
       static_cast<FileDescriptorWatcher*>(context);
   DCHECK(controller);
-  TRACE_EVENT1("toplevel", "MessagePumpLibevent::OnLibeventNotification",
-               "fd", fd);
+  TRACE_EVENT2("toplevel", "MessagePumpLibevent::OnLibeventNotification",
+               "src_file", controller->created_from_location().file_name(),
+               "src_func", controller->created_from_location().function_name());
+  TRACE_HEAP_PROFILER_API_SCOPED_TASK_EXECUTION heap_profiler_scope(
+      controller->created_from_location().file_name());
 
   MessagePumpLibevent* pump = controller->pump();
   pump->processed_io_events_ = true;
 
   if ((flags & (EV_READ | EV_WRITE)) == (EV_READ | EV_WRITE)) {
     // Both callbacks will be called. It is necessary to check that |controller|
     // is not destroyed.
     bool controller_was_destroyed = false;
     controller->was_destroyed_ = &controller_was_destroyed;
     controller->OnFileCanWriteWithoutBlocking(fd, pump);
@@ skipping 17 matching lines @@
   // Remove and discard the wakeup byte.
   char buf;
   int nread = HANDLE_EINTR(read(socket, &buf, 1));
   DCHECK_EQ(nread, 1);
   that->processed_io_events_ = true;
   // Tell libevent to break out of inner loop.
   event_base_loopbreak(that->event_base_);
 }
 
 }  // namespace base