README for sel_universal with ppapi emultation via SDL


The idea is to allow simple games to be tested outside of the browser
under sel_universal.
Those games are expected to be written using naclports' SDL wrapper.
The ppapi calls resulting from the wrapper are not using all
of ppapi and the usage follows certain patterns.

sel_universal's ppapi emulation transforms the ppapi related SRPC calls into
equivalent SDL calls.

The high level picture looks something like this:
untrusted SDL -> untrusted PPAPI -> sel_universal -> trusted SDL


What works:
* Very limited 2d functionality, expects one image_data object to be
  flushed into one graphics object (of same size) periodically
* Limited keyboard and mouse events
* Sound support (only one audio and one audio_config object)

Near term goals:
* Readonly file support
* (Maybe) port to fake_browser

(Very) long term goals:
* more general support for ppapi
* debug and analysis tools


How to build the enhanced sel_universal:

./scons platform=x86-64 --mode=opt-linux sel_universal sdl_sel_universal=1

How to run the enhanced sel_universal:

scons-out/opt-linux-x86-64/staging/sel_universal -- scons-out/nacl-x86-64/staging/ppapi_example_2d.nexe < src/trusted/sel_universal/launch.stdin
