tree 0e61d7fe47075443b2c88e65f7fd391a36a62c51
parent ebffb8dbc0a4ef6e8ae0dea3ee000dfb37797aa2
author Todd Wang <toddw@google.com> 1429641404 -0700
committer Todd Wang <toddw@google.com> 1429641405 -0700

playground: Add OverrideCaveatSetsValidator for use by wspr and jni.

Before this CL, we had two different mechanisms to override
caveat validation.  Javascript (wspr) used a "hidden context key"
to pass a custom validator around, while Java (jni) used
security.SetCaveatValidator to set a custom function.  The wspr
technique overrode the validation for all caveat sets in a
blessing, while the jni technique overrode the validation of each
individual caveat.

This CL reduces us back to a single mechanism
security.OverrideCaveatSetsValidator.  This function is only
available if the "android", "nacl" or "wspr" build tags is set,
and will panic if called more than once.  We restrict to these
build tags as a way to limit the exposure of the API.

MultiPart: 6/6
Change-Id: I27307345d534405466b615ad3cfedb5b3fda3ac3