Add hook for extension to check sync status.

chrome/browser/extensions/api/preferences_private/preferences_private_api.h

+// 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_PREFERENCES_PRIVATE_PREFERENCES_PRIVATE_API_H_
+#define CHROME_BROWSER_EXTENSIONS_API_PREFERENCES_PRIVATE_PREFERENCES_PRIVATE_API_H_
+
+#include "base/basictypes.h"
+#include "chrome/browser/extensions/chrome_extension_function.h"
+#include "chrome/browser/extensions/extension_function_histogram_value.h"
+#include "chrome/browser/sync/profile_sync_service_observer.h"
+#include "extensions/browser/extension_function.h"
+
+namespace extensions {
+
+class PreferencesPrivateGetSyncCategoriesWithoutPassphraseFunction
+    : public ChromeAsyncExtensionFunction, public ProfileSyncServiceObserver {
+ public:
+  DECLARE_EXTENSION_FUNCTION(
+      "preferencesPrivate.getSyncCategoriesWithoutPassphrase",
+      PREFERENCESPRIVATE_GETSYNCCATEGORIESWITHOUTPASSPHRASE)
+
+  PreferencesPrivateGetSyncCategoriesWithoutPassphraseFunction();
+
+ protected:
+  virtual ~PreferencesPrivateGetSyncCategoriesWithoutPassphraseFunction();
+
+ private:
+  // ProfileSyncServiceObserver:
+  virtual void OnStateChanged() OVERRIDE;
+
+  // ExtensionFunction:
+  virtual bool RunImpl() OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(
+      PreferencesPrivateGetSyncCategoriesWithoutPassphraseFunction);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_PREFERENCES_PRIVATE_PREFERENCES_PRIVATE_API_H_