Don't fire idle active event when listener re-added

chrome/browser/extensions/api/idle/idle_manager.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 "chrome/browser/extensions/api/idle/idle_manager.h"
 
 #include <utility>
 
 #include "base/stl_util.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 153 matching lines @@
 }
 
 void IdleManager::OnListenerRemoved(const EventListenerInfo& details) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // During unload the monitor could already have been deleted. No need to do
   // anything in that case.
   MonitorMap::iterator it = monitors_.find(details.extension_id);
   if (it != monitors_.end()) {
     DCHECK_GT(it->second.listeners, 0);
+    // Note: Deliberately leave the listener count as 0 rather than erase()ing
+    // this record so that the threshold doesn't get reset when all listeners
+    // are removed.
     --it->second.listeners;
   }
 }
 
 void IdleManager::QueryState(int threshold, QueryStateCallback notify) {
   DCHECK(thread_checker_.CalledOnValidThread());
   idle_time_provider_->CalculateIdleState(threshold, notify);
 }
 
 void IdleManager::SetThreshold(const std::string& extension_id,
@@ skipping 68 matching lines @@
   bool locked = idle_time_provider_->CheckIdleStateIsLocked();
   int listener_count = 0;
 
   // Remember this state for initializing new event listeners.
   last_state_ = IdleTimeToIdleState(locked,
                                     idle_time,
                                     kDefaultIdleThreshold);
 
   for (MonitorMap::iterator it = monitors_.begin();
        it != monitors_.end(); ++it) {
-    if (it->second.listeners < 1)
-      continue;
-
-    ++listener_count;
-
-    IdleState new_state = IdleTimeToIdleState(locked,
-                                              idle_time,
-                                              it->second.threshold);
-
-    if (new_state != it->second.last_state) {
-      it->second.last_state = new_state;
+    IdleMonitor& monitor = it->second;
+    IdleState new_state =
+        IdleTimeToIdleState(locked, idle_time, monitor.threshold);
+    // TODO(kalman): Use EventRouter::HasListeners for these sorts of checks.
+    if (monitor.listeners > 0 && monitor.last_state != new_state)
       event_delegate_->OnStateChanged(it->first, new_state);
-    }
+    monitor.last_state = new_state;
+    listener_count += monitor.listeners;
   }
 
-  if (listener_count == 0) {
+  if (listener_count == 0)
     StopPolling();
-  }
 }
 
 }  // namespace extensions