chrome.settingsPrivate: Implement onPrefsChanged event handling.

chrome/browser/extensions/api/settings_private/prefs_util.h

+// Copyright 2015 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_SETTINGS_PRIVATE_PREFS_UTIL_H_
+#define CHROME_BROWSER_EXTENSIONS_API_SETTINGS_PRIVATE_PREFS_UTIL_H_
+
+#include <map>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/common/extensions/api/settings_private.h"
+
+class PrefService;
+class Profile;
+
+namespace extensions {
+
+namespace prefs_util {
+
+using TypedPrefMap = std::map<std::string, api::settings_private::PrefType>;
+
+// Gets the list of whitelisted pref keys -- that is, those which correspond to
+// prefs that clients of the settingsPrivate API may retrieve and manipulate.
+const TypedPrefMap& GetWhitelistedKeys();
+
+// Gets the value of the pref with the given |name|. Returns a pointer to an
+// empty PrefObject if no pref is found for |name|.
+scoped_ptr<api::settings_private::PrefObject> GetPref(Profile* profile,
+                                                      const std::string& name);
+
+// Returns whether |pref_name| corresponds to a pref whose type is URL.
+bool IsPrefTypeURL(const std::string& pref_name);
+
+// Returns whether |pref_name| corresponds to a pref that is user modifiable
+// (i.e., not made restricted by a user or device policy).
+bool IsPrefUserModifiable(Profile* profile, const std::string& pref_name);
+
+// Returns a pointer to the appropriate PrefService instance for the given
+// |pref_name|.
+PrefService* FindServiceForPref(Profile* profile, const std::string& pref_name);
+
+}  // namespace prefs_util
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_SETTINGS_PRIVATE_PREFS_UTIL_H_