Make chrome.alarms API accept non-integers and too-short delays.

chrome/browser/extensions/api/alarms/alarm_manager.cc

Index: chrome/browser/extensions/api/alarms/alarm_manager.cc
diff --git a/chrome/browser/extensions/api/alarms/alarm_manager.cc b/chrome/browser/extensions/api/alarms/alarm_manager.cc
index 11282daba896015d03d6ef5d1ddb4597e1d1b0cf..a0bf73f901d8330818638ef2160e46e65e7a14b9 100644
--- a/chrome/browser/extensions/api/alarms/alarm_manager.cc
+++ b/chrome/browser/extensions/api/alarms/alarm_manager.cc
@@ -29,7 +29,7 @@ const char kRegisteredAlarms[] = "alarms";
 const char kAlarmGranularity[] = "granularity";
 
 // The minimum period between polling for alarms to run.
-const base::TimeDelta kDefaultMinPollPeriod = base::TimeDelta::FromMinutes(1);
+const base::TimeDelta kDefaultMinPollPeriod = base::TimeDelta::FromDays(1);
 
 class DefaultAlarmDelegate : public AlarmManager::Delegate {
  public:
@@ -207,8 +207,7 @@ void AlarmManager::AddAlarmImpl(const std::string& extension_id,
 
   alarms_[extension_id].push_back(alarm);
 
-  // TODO(yoz): Is 0 really sane? There could be thrashing.
-  ScheduleNextPoll(base::TimeDelta::FromMinutes(0));
+  ScheduleNextPoll();
 }
 
 void AlarmManager::WriteToStorage(const std::string& extension_id) {
@@ -237,7 +236,7 @@ void AlarmManager::ReadFromStorage(const std::string& extension_id,
   }
 }
 
-void AlarmManager::ScheduleNextPoll(base::TimeDelta min_period) {
+void AlarmManager::ScheduleNextPoll() {
   // 0. If there are no alarms, stop the timer.
   if (alarms_.empty()) {
     timer_.Stop();
@@ -247,12 +246,12 @@ void AlarmManager::ScheduleNextPoll(base::TimeDelta min_period) {
   // TODO(yoz): Try not to reschedule every single time if we're adding
   // a lot of alarms.
 
-  base::Time next_poll(last_poll_time_ + min_period);
-
-  // Find the soonest alarm that is scheduled to run.
+  // Find the soonest alarm that is scheduled to run and the smallest
+  // granularity of any alarm.
   // alarms_ guarantees that none of its contained lists are empty.
   base::Time soonest_alarm_time = base::Time::FromJsTime(
       alarms_.begin()->second.begin()->js_alarm->scheduled_time);
+  base::TimeDelta min_granularity = kDefaultMinPollPeriod;
   for (AlarmMap::const_iterator m_it = alarms_.begin(), m_end = alarms_.end();
        m_it != m_end; ++m_it) {
     for (AlarmList::const_iterator l_it = m_it->second.begin();
@@ -261,14 +260,18 @@ void AlarmManager::ScheduleNextPoll(base::TimeDelta min_period) {
           base::Time::FromJsTime(l_it->js_alarm->scheduled_time);
       if (cur_alarm_time < soonest_alarm_time)
         soonest_alarm_time = cur_alarm_time;
+      if (l_it->granularity < min_granularity)
+        min_granularity = l_it->granularity;
     }
   }
 
-  // If the next alarm is more than min_period in the future, wait for it.
-  // Otherwise, only poll as often as min_period.
-  if (last_poll_time_.is_null() || next_poll < soonest_alarm_time) {
+  base::Time next_poll(last_poll_time_ + min_granularity);
+  // If the next alarm is more than min_granularity in the future, wait for it.
+  // Otherwise, only poll as often as min_granularity.
+  // As a special case, if we've never checked for an alarm before
+  // (e.g. during startup), let alarms fire asap.
+  if (last_poll_time_.is_null() || next_poll < soonest_alarm_time)
     next_poll = soonest_alarm_time;
-  }
 
   // Schedule the poll.
   next_poll_time_ = next_poll;
@@ -303,19 +306,7 @@ void AlarmManager::PollAlarms() {
     }
   }
 
-  // Schedule the next poll. The soonest it may happen is after
-  // kDefaultMinPollPeriod or after the shortest granularity of any alarm,
-  // whichever comes sooner.
-  base::TimeDelta min_poll_period = kDefaultMinPollPeriod;
-  for (AlarmMap::const_iterator m_it = alarms_.begin(), m_end = alarms_.end();
-       m_it != m_end; ++m_it) {
-    for (AlarmList::const_iterator l_it = m_it->second.begin();
-         l_it != m_it->second.end(); ++l_it) {
-      if (l_it->granularity < min_poll_period)
-        min_poll_period = l_it->granularity;
-    }
-  }
-  ScheduleNextPoll(min_poll_period);
+  ScheduleNextPoll();
 }
 
 void AlarmManager::Observe(