Initial chrome.mdns API.

chrome/browser/extensions/api/mdns/mdns_api.h

+// Copyright (c) 2013 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.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_MDNS_MDNS_API_H_
+#define CHROME_BROWSER_EXTENSIONS_API_MDNS_MDNS_API_H_
+
+#include <set>
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/extensions/api/mdns/nsd_registry.h"
+#include "chrome/browser/extensions/api/profile_keyed_api_factory.h"
+#include "chrome/browser/extensions/event_router.h"
+
+namespace extensions {
+
+class NsdRegistry;
+
+// MDnsAPI is instantiated with the profile and will listen for extensions that
+// register listeners for the chrome.mdns extension API. It will use an Network
+// Service Discovery type registry class to start the mDNS listener process (if
+// necessary) and observe new service events to dispatch them to registered
+// extensions. The Network Service Discovery registry is a location for
+// managing discovery protocols.

[mark a. foltz, 2013/09/06 00:15:49]

The way this is described it sounds more like an NsdApi since it exposes the
NsdRegistry to extensions.  Perhaps this is the right separation of concerns but
I feel like the naming should be made a bit more consistent.  Maybe NsdRegistry
should be DnsSdRegistry?

I don't feel strongly.

[justinlin, 2013/09/06 00:39:29]

Done. Yes, I think that makes sense. Renamed NsdRegistry to DnsSdRegistry. The
api name is still mdns for now since mdns is more general.

+class MDnsAPI : public ProfileKeyedAPI,
+                public EventRouter::Observer,
+                public NsdRegistry::NsdObserver {
+ public:
+  explicit MDnsAPI(Profile* profile);
+  virtual ~MDnsAPI();
+
+  static MDnsAPI* Get(Profile* profile);
+
+  // ProfileKeyedAPI implementation.
+  static ProfileKeyedAPIFactory<MDnsAPI>* GetFactoryInstance();
+
+  // Used to mock out the NsdRegistry for testing.
+  void SetNsdRegistryForTesting(scoped_ptr<NsdRegistry> registry);
+
+ protected:
+  // Retrieve an instance of the registry. Lazily created when needed.
+  virtual NsdRegistry* nsd_registry();
+
+ private:
+  friend class ProfileKeyedAPIFactory<MDnsAPI>;
+
+  // EventRouter::Observer:
+  virtual void OnListenerAdded(const EventListenerInfo& details) OVERRIDE;
+  virtual void OnListenerRemoved(const EventListenerInfo& details) OVERRIDE;
+
+  // NsdRegistry::Observer
+  virtual void OnMDnsEvent(

[mark a. foltz, 2013/09/06 00:15:49]

OnDnsSdEvent?

[justinlin, 2013/09/06 00:39:29]

Done.

+      const std::string& service_type,
+      const NsdRegistry::NsdServiceList& services) OVERRIDE;
+
+  // ProfileKeyedAPI implementation.
+  static const char* service_name() {
+    return "MDnsAPI";
+  }
+
+  static const bool kServiceIsCreatedWithBrowserContext = true;
+  static const bool kServiceIsNULLWhileTesting = true;
+
+  // Update the current list of service types and update the NSD registry.
+  void UpdateMDnsListeners(const EventListenerInfo& details);
+
+  // Ensure methods are only called on UI thread.
+  base::ThreadChecker thread_checker_;
+  Profile* const profile_;
+  // Lazily created on first access and destroyed with this API class.
+  scoped_ptr<NsdRegistry> nsd_registry_;
+  // Current set of service types registered with the NSD registry.
+  std::set<std::string> service_types_;
+
+  DISALLOW_COPY_AND_ASSIGN(MDnsAPI);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_MDNS_MDNS_API_H_