Adding support for traversing the content of a node info at granularity.

Adding support for traversing the content of a node info at granularity.

1. A view that creates an accessibility node info may add to the info
   a list of granularity labels. These are granularities by which the
   source view can iterate over its content. For example a text view
   may support character, word link while a web view may additionally
   support buttons, tables, etc. There are actions on accessibility
   node info to go to the next/previous at a given granularity which
   is passesed as an argument.

2. Added Bundle argument to the APIs for performing accessibility
   actions. This is generic and extensible.

bug:5932640

Change-Id: I328cbbb4cddfdee082ab2a8b7ff1bd7477d8d6f9