Implement mediaGalleriesPrivate api to notify extensions about gallery changed events.

chrome/test/data/extensions/api_test/media_galleries_private/gallerywatch/test.js

+// 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.
+
+var galleries;
+var invalidGalleryId = 11000;
+
+// chrome.mediaGalleries.getMediaFileSystems callback.
+var mediaFileSystemsListCallback = function (results) {
+  galleries = results;
+  chrome.test.sendMessage('get_media_file_systems_callback_ok');
+};
+
+// Gallery changed event handler.
+var onGalleryChangedCallback = function (details) {
+  chrome.test.sendMessage('gallery_changed_event_received');
+};
+
+// Add watch request callback.
+var onAddWatchRequestCallback = function (details) {
+  if (!details || !details.success)
+    chrome.test.sendMessage('add_watch_request_failed');
+  else
+    chrome.test.sendMessage('add_watch_request_succeeded');
+};
+
+// Helpers to add and remove event listeners.
+function addGalleryChangedListener() {
+  chrome.mediaGalleriesPrivate.onGalleryChanged.addListener(
+      onGalleryChangedCallback);
+  chrome.test.sendMessage('add_gallery_changed_listener_ok');
+};
+
+function setupWatchOnValidGalleries() {
+  for (var i = 0; i < galleries.length; ++i) {
+    var info = JSON.parse(galleries[i].name);
+    chrome.mediaGalleriesPrivate.addGalleryWatch(info.galleryId,
+                                                 onAddWatchRequestCallback);
+  }
+  chrome.test.sendMessage('add_gallery_watch_ok');
+};
+
+function setupWatchOnInvalidGallery() {
+  chrome.mediaGalleriesPrivate.addGalleryWatch(invalidGalleryId,
+                                               onAddWatchRequestCallback);
+  chrome.test.sendMessage('add_gallery_watch_ok');
+}
+
+function getMediaFileSystems() {
+  chrome.mediaGalleries.getMediaFileSystems(mediaFileSystemsListCallback);
+  chrome.test.sendMessage('get_media_file_systems_ok');
+};
+
+function removeGalleryWatch() {
+  for (var i = 0; i < galleries.length; ++i) {
+    var info = JSON.parse(galleries[i].name);
+    chrome.mediaGalleriesPrivate.removeGalleryWatch(info.galleryId);
+  }
+  chrome.test.sendMessage('remove_gallery_watch_ok');
+};
+
+function removeGalleryChangedListener() {
+  chrome.mediaGalleriesPrivate.onGalleryChanged.removeListener(
+      onGalleryChangedCallback);
+  chrome.test.sendMessage('remove_gallery_changed_listener_ok');
+};