Add support for ISA choosing from a manifest file.  Note that this CL parses the JSON by calling 'eval' in the browser, which is distressing.  Tracked by bug http://code.google.com/p/nativeclient/issues/detail?id=1038
Add support for ISA choosing from a manifest file.  Note that this CL parses
the JSON by calling 'eval' in the browser, which is distressing.  Tracked by bug
http://code.google.com/p/nativeclient/issues/detail?id=1038

BUG = http://code.google.com/p/nativeclient/issues/detail?id=1039
http://code.google.com/p/nativeclient/issues/detail?id=885
TEST = none (see bug http://code.google.com/p/nativeclient/issues/detail?id=1041)


Review URL: http://codereview.chromium.org/4831004

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@3722 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client