Link GCM heartbeat with wake on wifi preference

components/timers/rtc_alarm.cc

 // Copyright 2014 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 "components/timers/rtc_alarm.h"
 
 #include <sys/timerfd.h>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 70 matching lines @@
 
   // Increment the event id.  Used to invalidate any events that have been
   // queued but not yet run since the last time Reset() was called.
   origin_event_id_++;
 
   // Calling timerfd_settime with a zero delay actually clears the timer so if
   // the user has requested a zero delay timer, we need to handle it
   // differently.  We queue the task here but we still go ahead and call
   // timerfd_settime with the zero delay anyway to cancel any previous delay
   // that might have been programmed.
-  if (delay == base::TimeDelta()) {
+  if (delay <= base::TimeDelta::FromMicroseconds(0)) {

[Daniel Erat, 2014/12/04 23:23:16]

any reason you can't use the shorter base::TimeDelta() here and below? that's
what i usually use when i want a zero-length delta.

[Chirantan Ekbote, 2014/12/04 23:31:40]

I did it mainly to make it painfully explicit and to be consistent with how
base::Timer performs this check.  I can change it to base::TimeDelta() though.

+    // The timerfd_settime documentation is vague on what happens when it is
+    // passed a negative delay.  We can sidestep the issue by ensuring that the
+    // delay is 0.
+    delay = base::TimeDelta::FromMicroseconds(0);
     origin_message_loop_->PostTask(FROM_HERE,
                                    base::Bind(&RtcAlarm::OnTimerFired,
                                               scoped_refptr<RtcAlarm>(this),
                                               origin_event_id_));
   }
 
   // Make sure that we are running on a MessageLoopForIO.
   if (!base::MessageLoopForIO::IsCurrent()) {
     g_io_thread.Get()->task_runner()->PostTask(
         FROM_HERE,
@@ skipping 71 matching lines @@
   // this task was queued to run and now.  If it was reset, then don't do
   // anything.
   if (event_id != origin_event_id_)
     return;
 
   if (parent_)
     parent_->OnTimerFired();
 }
 
 }  // namespace timers