Change MessagePumpLibevent::Run to handle IO events before doing idle

base/message_pump_libevent.cc

 // Copyright (c) 2011 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_pump_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 
 #include "base/auto_reset.h"
@@ skipping 208 matching lines @@
   // Instead, make our own timer and reuse it on each call to event_base_loop().
   scoped_ptr<event> timer_event(new event);
 
   for (;;) {
     mac::ScopedNSAutoreleasePool autorelease_pool;
 
     bool did_work = delegate->DoWork();
     if (!keep_running_)
       break;
 
+    int rv = event_base_loop(event_base_, EVLOOP_NONBLOCK);
+    did_work |= (rv == 2);
+
     did_work |= delegate->DoDelayedWork(&delayed_work_time_);
     if (!keep_running_)
       break;
 
     if (did_work)
       continue;
 
     did_work = delegate->DoIdleWork();
     if (!keep_running_)
       break;
 
     if (did_work)
       continue;
 
     // EVLOOP_ONCE tells libevent to only block once,
     // but to service all pending events when it wakes up.
     if (delayed_work_time_.is_null()) {
       event_base_loop(event_base_, EVLOOP_ONCE);

[wtc, 2011/06/25 00:39:45]

The original code calls event_base_loop here and on line
259 below, after the delegate->DoIdleWork() call.

     } else {
       TimeDelta delay = delayed_work_time_ - TimeTicks::Now();
       if (delay > TimeDelta()) {
         struct timeval poll_tv;
         poll_tv.tv_sec = delay.InSeconds();
         poll_tv.tv_usec = delay.InMicroseconds() % Time::kMicrosecondsPerSecond;
         event_set(timer_event.get(), -1, 0, timer_callback, event_base_);
         event_base_set(event_base_, timer_event.get());
         event_add(timer_event.get(), &poll_tv);
         event_base_loop(event_base_, EVLOOP_ONCE);
@@ skipping 92 matching lines @@
 
   // Remove and discard the wakeup byte.
   char buf;
   int nread = HANDLE_EINTR(read(socket, &buf, 1));
   DCHECK_EQ(nread, 1);
   // Tell libevent to break out of inner loop.
   event_base_loopbreak(that->event_base_);
 }
 
 }  // namespace base