Add a folders_only and subtree api to bookmark manager

Adds a new API to the experimental.bookmarkManager namespace

getSubtree(id, foldersOnly, callback)

Which returns any subtree, and if foldersOnly is true, only returns the folders.
At this point, only the bookmark tree is using the new call.

BUG=39877
TEST=ExtensionBookmarksTest.*

Review URL: http://codereview.chromium.org/1611001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43461 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_function_dispatcher.cc b/chrome/browser/extensions/extension_function_dispatcher.cc
index 03889eec..78a2c032 100644
--- a/chrome/browser/extensions/extension_function_dispatcher.cc
+++ b/chrome/browser/extensions/extension_function_dispatcher.cc
@@ -156,6 +156,7 @@
   RegisterFunction<BookmarkManagerGetStringsFunction>();
   RegisterFunction<StartDragBookmarkManagerFunction>();
   RegisterFunction<DropBookmarkManagerFunction>();
+  RegisterFunction<GetSubtreeBookmarkManagerFunction>();
 
   // History
   RegisterFunction<AddUrlHistoryFunction>();