Media Galleries: Add chrome.mediaGalleries.addUserSelectedFolder().

chrome/renderer/resources/extensions/media_galleries_custom_bindings.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.
 
 // Custom binding for the Media Gallery API.
 
 var binding = require('binding').Binding.create('mediaGalleries');
 
 var mediaGalleriesNatives = requireNative('mediaGalleries');
 var blobNatives = requireNative('blob_natives');
 
 var mediaGalleriesMetadata = {};
 
+function createFileSystemObjectsAndUpdateMetadata(response) {
+  var result = null;
+  mediaGalleriesMetadata = {};  // Clear any previous metadata.
+  if (response) {
+    result = [];
+    for (var i = 0; i < response.length; i++) {
+      var filesystem = mediaGalleriesNatives.GetMediaFileSystemObject(
+          response[i].fsid);
+      $Array.push(result, filesystem);
+      var metadata = response[i];
+      delete metadata.fsid;
+      mediaGalleriesMetadata[filesystem.name] = metadata;
+    }
+  }
+  return result;
+}
+
 binding.registerCustomHook(function(bindingsAPI, extensionId) {
   var apiFunctions = bindingsAPI.apiFunctions;
 
   // getMediaFileSystems uses a custom callback so that it can instantiate and
   // return an array of file system objects.
   apiFunctions.setCustomCallback('getMediaFileSystems',
                                  function(name, request, response) {
-    var result = null;
-    mediaGalleriesMetadata = {};  // Clear any previous metadata.
-    if (response) {
-      result = [];
-      for (var i = 0; i < response.length; i++) {
-        var filesystem = mediaGalleriesNatives.GetMediaFileSystemObject(
-            response[i].fsid);
-        $Array.push(result, filesystem);
-        var metadata = response[i];
-        delete metadata.fsid;
-        mediaGalleriesMetadata[filesystem.name] = metadata;
-      }
+    var result = createFileSystemObjectsAndUpdateMetadata(response);
+    if (request.callback)
+      request.callback(result);
+    request.callback = null;
+  });
+
+  // addUserSelectedFolder uses a custom callback so that it can instantiate
+  // and return an array of file system objects.
+  apiFunctions.setCustomCallback('addUserSelectedFolder',
+                                 function(name, request, response) {
+    var fileSystems = [];
+    var selectedFileSystemName = "";
+    if (response && response.length > 0) {
+      selectedFileSystemName = response.pop()
+      fileSystems = createFileSystemObjectsAndUpdateMetadata(response);
     }
     if (request.callback)
-      request.callback(result);
+      request.callback(fileSystems, selectedFileSystemName);
     request.callback = null;
   });
 
   apiFunctions.setHandleRequest('getMediaFileSystemMetadata',
                                 function(filesystem) {
     if (filesystem && filesystem.name &&
         mediaGalleriesMetadata[filesystem.name]) {
       return mediaGalleriesMetadata[filesystem.name];
     }
     return {};
   });
 
   apiFunctions.setUpdateArgumentsPostValidate('getMetadata',
       function(mediaFile, options, callback) {
     var blobUuid = blobNatives.GetBlobUuid(mediaFile)
     return [blobUuid, options, callback];
   });
 });
 
 exports.binding = binding.generate();