Fix crash during ChromeOS login

chrome/browser/extensions/system/system_api.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/system/system_api.h"
 
 #include "base/json/json_writer.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_event_router.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ skipping 32 matching lines @@
 const char kNeedRestartState[] = "NeedRestart";
 
 // Event names.
 const char kOnBrightnessChanged[] = "systemPrivate.onBrightnessChanged";
 const char kOnVolumeChanged[] = "systemPrivate.onVolumeChanged";
 const char kOnScreenUnlocked[] = "systemPrivate.onScreenUnlocked";
 const char kOnWokeUp[] = "systemPrivate.onWokeUp";
 
 // Dispatches an extension event with |args|
 void DispatchEvent(const std::string& event_name, const ListValue& args) {
+  Profile* profile = ProfileManager::GetDefaultProfile();
+  if (!profile)
+    return;
+  ExtensionEventRouter* extension_event_router =
+      profile->GetExtensionEventRouter();
+  if (!extension_event_router)
+    return;
   std::string json_args;
   base::JSONWriter::Write(&args, false, &json_args);
-  ProfileManager::GetDefaultProfile()->GetExtensionEventRouter()->
-      DispatchEventToRenderers(event_name, json_args, NULL, GURL());
+  extension_event_router->DispatchEventToRenderers(
+      event_name, json_args, NULL, GURL());
 }
 
 }  // namespace
 
 namespace extensions {
 
 bool GetIncognitoModeAvailabilityFunction::RunImpl() {
   PrefService* prefs = profile_->GetPrefs();
   int value = prefs->GetInteger(prefs::kIncognitoModeAvailability);
   EXTENSION_FUNCTION_VALIDATE(
@@ skipping 87 matching lines @@
   ListValue args;
   DispatchEvent(kOnScreenUnlocked, args);
 }
 
 void DispatchWokeUpEvent() {
   ListValue args;
   DispatchEvent(kOnWokeUp, args);
 }
 
 }  // namespace extensions