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

chrome/common/extensions/api/media_galleries.idl

Index: chrome/common/extensions/api/media_galleries.idl
===================================================================
--- chrome/common/extensions/api/media_galleries.idl	(revision 243958)
+++ chrome/common/extensions/api/media_galleries.idl	(working copy)
@@ -41,6 +41,10 @@
   callback MediaFileSystemsCallback =
       void ([instanceOf=DOMFileSystem] optional object[] mediaFileSystems);
 
+  callback AddUserFolderCallback =
+      void ([instanceOf=DOMFileSystem] object[] mediaFileSystems,
+            DOMString selectedFileSystemName);
+
   [inline_doc] dictionary MediaFileSystemMetadata {
     // The name of the file system.
     DOMString name;
@@ -97,6 +101,11 @@
     static void getMediaFileSystems(optional MediaFileSystemsDetails details,
                                     MediaFileSystemsCallback callback);
 
+    // Present a directory picker to the user and add the selected directory
+    // as a gallery. If the user cancels the picker, selectedFileSystemName
+    // will be empty.
+    static void addUserSelectedFolder(AddUserFolderCallback callback);
+
     // Get metadata about a specific media file system.
     [nocompile] static MediaFileSystemMetadata getMediaFileSystemMetadata(
         [instanceOf=DOMFileSystem] object mediaFileSystem);