Fixed a possible memory leak and support null pointers in AutomationEventObservers' NotifyEvent.

chrome/browser/automation/automation_event_queue.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 <algorithm>
 
+#include "base/logging.h"
 #include "chrome/browser/automation/automation_event_observers.h"
 #include "chrome/browser/automation/automation_event_queue.h"
 #include "chrome/browser/automation/automation_provider_json.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 
 AutomationEventQueue::CompareObserverId::CompareObserverId(int id) : id_(id) {}
 
 bool AutomationEventQueue::CompareObserverId::operator()(
     AutomationEvent* event) const {
@@ skipping 50 matching lines @@
                    CompareObserverId(observer_id));
   if (it != event_queue_.rend()) {
     event = *it;
     event_queue_.remove(event);
   }
   return event;
 }
 
 void AutomationEventQueue::NotifyEvent(
     AutomationEventQueue::AutomationEvent* event) {
+  DCHECK(event);
+  VLOG(2) << "AutomationEventQueue::NotifyEvent id=" << event->GetId();
   event_queue_.push_front(event);
   CheckReturnEvent();
 }
 
 int AutomationEventQueue::AddObserver(AutomationEventObserver* observer) {
   int id = observer_id_count_++;
   observer->Init(id);
   observers_[id] = observer;
   return id;
 }
 
 bool AutomationEventQueue::RemoveObserver(int observer_id) {
   if (observers_.find(observer_id) != observers_.end()) {
+    VLOG(2) << "AutomationEventQueue::RemoveObserver id=" << observer_id;
     delete observers_[observer_id];
     observers_.erase(observer_id);
     return true;
   }
   return false;
 }
 
 void AutomationEventQueue::ClearObservers() {
   std::map<int, AutomationEventObserver*>::iterator it;
   for (it = observers_.begin(); it != observers_.end(); it++) {
@@ skipping 18 matching lines @@
     if (event) {
       wait_automation_reply_->SendSuccess(event->GetValue());
       wait_automation_reply_.reset();
       wait_observer_id_ = -1;
       delete event;
       return true;
     }
   }
   return false;
 }