R1:6d20a57ce07b

Instant subscribe/unsubscribe

Summary:
No workflow dialog when subscribing or unsubscribing from a Differential
Revision

Test Plan:
Repeatedly subscribe and unsubscribe to a revision. Enter refractory period due
to
speed of page gen.

Reviewed By: epriestley
Reviewers: epriestley
CC: epriestley
Differential Revision: 128