libeven message-pump: Fix a particular case of nested message-loop runs.

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>
 
@@ skipping 199 matching lines @@
 }
 
 // Tell libevent to break out of inner loop.
 static void timer_callback(int fd, short events, void *context)
 {
   event_base_loopbreak((struct event_base *)context);
 }
 
 // Reentrant!
 void MessagePumpLibevent::Run(Delegate* delegate) {
-  DCHECK(keep_running_) << "Quit must have been called outside of Run!";
+  AutoReset<bool> auto_reset_keep_running(&keep_running_, true);
   AutoReset<bool> auto_reset_in_run(&in_run_, true);
 
   // event_base_loopexit() + EVLOOP_ONCE is leaky, see http://crbug.com/25641.
   // Instead, make our own timer and reuse it on each call to event_base_loop().
   scoped_ptr<event> timer_event(new event);
 
   for (;;) {
 #if defined(OS_MACOSX)
     mac::ScopedNSAutoreleasePool autorelease_pool;
 #endif
@@ skipping 37 matching lines @@
         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();
       }
     }
   }
-
-  keep_running_ = true;
 }
 
 void MessagePumpLibevent::Quit() {
-  DCHECK(in_run_);
+  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();
 }
 
 void MessagePumpLibevent::ScheduleWork() {
   // Tell libevent (in a threadsafe way) that it should break out of its loop.
   char buf = 0;
   int nwrite = HANDLE_EINTR(write(wakeup_pipe_in_, &buf, 1));
   DCHECK(nwrite == 1 || errno == EAGAIN)
@@ skipping 72 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