Isolated FS for media devices.

base/system_monitor/system_monitor.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 "base/system_monitor/system_monitor.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 86 matching lines @@
     // This can happen if our unique id scheme fails. Ignore the incoming
     // non-unique attachment.
     return;
   }
   media_device_map_.insert(std::make_pair(id, info));
   NotifyMediaDeviceAttached(id, name, type, location);
 }
 
 void SystemMonitor::ProcessMediaDeviceDetached(const std::string& id) {
   MediaDeviceMap::iterator it = media_device_map_.find(id);
-  if (it != media_device_map_.end())
-    media_device_map_.erase(it);
+  if (it == media_device_map_.end())
+    return;
+  media_device_map_.erase(it);
   NotifyMediaDeviceDetached(id);
 }
 
 std::vector<SystemMonitor::MediaDeviceInfo>
 SystemMonitor::GetAttachedMediaDevices() const {
   std::vector<MediaDeviceInfo> results;
   for (MediaDeviceMap::const_iterator it = media_device_map_.begin();
        it != media_device_map_.end();
        ++it) {
     results.push_back(it->second);
@@ skipping 55 matching lines @@
 void SystemMonitor::NotifyResume() {
   DVLOG(1) << "Power Resuming";
   power_observer_list_->Notify(&PowerObserver::OnResume);
 }
 
 void SystemMonitor::BatteryCheck() {
   ProcessPowerMessage(SystemMonitor::POWER_STATE_EVENT);
 }
 
 }  // namespace base