Graceful shutdown of UsbService

chrome/browser/usb/usb_service.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/usb/usb_service.h"
 
 #include <set>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 20 matching lines @@
 }  // namespace content
 
 using content::BrowserThread;
 using std::vector;
 
 namespace {
 
 class ExitObserver : public content::NotificationObserver {
  public:
   explicit ExitObserver(UsbService* service) : service_(service) {
-    registrar_.Add(this, chrome::NOTIFICATION_APP_TERMINATING,
-                   content::NotificationService::AllSources());
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&content::NotificationRegistrar::Add,
+                   base::Unretained(&registrar_), this,
+                   chrome::NOTIFICATION_APP_TERMINATING,
+                   content::NotificationService::AllSources()));
   }
 
  private:
   // content::NotificationObserver
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE {
     if (type == chrome::NOTIFICATION_APP_TERMINATING) {
-      registrar_.RemoveAll();
       BrowserThread::DeleteSoon(BrowserThread::FILE, FROM_HERE, service_);
+      delete this;
     }
   }
   UsbService* service_;
   content::NotificationRegistrar registrar_;
 };
 
 }  // namespace
 
 using content::BrowserThread;
 
 UsbService::UsbService()
     : context_(new UsbContext()),
       next_unique_id_(0) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  // Will be deleted upon NOTIFICATION_APP_TERMINATING.
+  new ExitObserver(this);
 }
 
 UsbService::~UsbService() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
     it->second->OnDisconnect();
   }
 }
 
 UsbService* UsbService::GetInstance() {
@@ skipping 60 matching lines @@
 
   // Remove disconnected devices from devices_.
   for (size_t i = 0; i < disconnected_devices.size(); ++i) {
     // UsbDevice will be destroyed after this. The corresponding
     // PlatformUsbDevice will be unref'ed during this process.
     devices_.erase(disconnected_devices[i]);
   }
 
   libusb_free_device_list(platform_devices, true);
 }