Implemented types.private.ChromeDirectSetting.onChange

This delta links up the onChange event machinery to the property
change notification machinery.

It follows a pattern established in PreferencesAPI and the
PreferenceEventRouter.
* Given a list of preferences, register event listener added
  observers to each preference.
* On the first added event listener, unregister all observers
  and register all property change listeners.
* On property changes, forward an event to each component
  extension that has a property listener added.

BUG=164227

Review URL: https://chromiumcodereview.appspot.com/18100007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@212307 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 60 insertions, 0 deletions

diff --git a/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h
new file mode 100644
index 0000000..0fd6207
--- /dev/null
+++ b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h
@@ -0,0 +1,60 @@
+// Copyright 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_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+#define CHROME_BROWSER_EXTENSIONS_API_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+
+#include "chrome/browser/extensions/api/profile_keyed_api_factory.h"
+#include "chrome/browser/extensions/event_router.h"
+
+class PrefChangeRegistrar;
+class Profile;
+
+namespace extensions {
+namespace chromedirectsetting {
+
+class ChromeDirectSettingAPI : public ProfileKeyedAPI,
+                               public EventRouter::Observer {
+ public:
+  explicit ChromeDirectSettingAPI(Profile* profile);
+
+  virtual ~ChromeDirectSettingAPI();
+
+  // BrowserContextKeyedService implementation.
+  virtual void Shutdown() OVERRIDE;
+
+  // ProfileKeyedAPI implementation.
+  static ProfileKeyedAPIFactory<ChromeDirectSettingAPI>* GetFactoryInstance();
+
+  // EventRouter::Observer implementation.
+  virtual void OnListenerAdded(const EventListenerInfo& details) OVERRIDE;
+
+  // Returns true if the preference is on the whitelist.
+  bool IsPreferenceOnWhitelist(const std::string& pref_key);
+
+  // Convenience method to get the ChromeDirectSettingAPI for a profile.
+  static ChromeDirectSettingAPI* Get(Profile* profile);
+
+ private:
+  friend class ProfileKeyedAPIFactory<ChromeDirectSettingAPI>;
+
+  // ProfileKeyedAPI implementation.
+  static const char* service_name();
+
+  void OnPrefChanged(PrefService* pref_service, const std::string& pref_key);
+
+  static const bool kServiceIsNULLWhileTesting = true;
+  static const bool kServiceRedirectedInIncognito = false;
+
+  PrefChangeRegistrar registrar_;
+  Profile* profile_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeDirectSettingAPI);
+};
+
+}  // namespace chromedirectsetting
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+