commit 07f72d79b4a9a6f26536a7d7df702a63010bac25
author Todd Wang <toddw@google.com> Thu Apr 16 19:41:25 2015 -0700
committer Todd Wang <toddw@google.com> Fri Apr 17 06:10:59 2015 +0000
tree 037b2846e8fa1be0379f5e22f7feaf672890c508
parent 3b597f7b5b91626c4269f615abd18c3d690c2a87

TBR playground: Move security.Call out of context.T.

This is a companion to the following sequence of changes:
https://vanadium-review.googlesource.com/#/q/topic:ctx_call

Again the purpose is to make our usage of context.T more
consistent, and the JS code is being changed to do the same
thing.

The main change is to get rid of security.GetCall and
security.SetCall.  This means we need to pass security.Call
around explicitly when necessary; rpc.ServerCall includes a
Security() method which returns the security.Call.

Here are the new APIs (none of these included security.Call
before this CL):

Authorize(*context.t, security.Call) error
Grant(*context.T, security.Call) (security.Blessings, error)
Dischargeable(*context.T, security.Call) error
Caveat.Validate(*context.T, security.Call) error
security.RemoteBlessingNames(*context.T, security.Call)
security.LocalBlessingNames(*context.T, security.Call)

MultiPart: 6/7

Change-Id: Iddae58634728eef0e1c3793c4ba7060bcea43ea2