Update from https://crrev.com/327068

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 <fcntl.h>
 #include <unistd.h>
 
 #include "base/auto_reset.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "third_party/libevent/event.h"
 
 #if defined(OS_MACOSX)
 #include "base/mac/scoped_nsautorelease_pool.h"
 #endif
 
 // Lifecycle of struct event
 // Libevent uses two main data structures:
 // struct event_base (of which there is one per message pump), and
 // struct event (of which there is roughly one per socket).
@@ skipping 239 matching lines @@
         event_base_set(event_base_, timer_event.get());
         event_add(timer_event.get(), &poll_tv);
         event_base_loop(event_base_, EVLOOP_ONCE);
         event_del(timer_event.get());
       } else {
         // It looks like delayed_work_time_ indicates a time in the past, so we
         // need to call DoDelayedWork now.
         delayed_work_time_ = TimeTicks();
       }
     }
+
+    if (!keep_running_)
+      break;
   }
 }
 
 void MessagePumpLibevent::Quit() {
   DCHECK(in_run_) << "Quit was called outside of Run!";
   // Tell both libevent and Run that they should break out of their loops.
   keep_running_ = false;
   ScheduleWork();
 }
 
@@ skipping 47 matching lines @@
     return false;
   return true;
 }
 
 // static
 void MessagePumpLibevent::OnLibeventNotification(int fd, short flags,
                                                  void* context) {
   WeakPtr<FileDescriptorWatcher> controller =
       static_cast<FileDescriptorWatcher*>(context)->weak_factory_.GetWeakPtr();
   DCHECK(controller.get());
+  TRACE_EVENT1("toplevel", "MessagePumpLibevent::OnLibeventNotification",
+               "fd", fd);
 
   MessagePumpLibevent* pump = controller->pump();
   pump->processed_io_events_ = true;
 
   if (flags & EV_WRITE) {
     controller->OnFileCanWriteWithoutBlocking(fd, pump);
   }
   // Check |controller| in case it's been deleted in
   // controller->OnFileCanWriteWithoutBlocking().
   if (controller.get() && flags & EV_READ) {
@@ skipping 10 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