Added Google Cache Invalidation library to DEPS and got it to compile
with the Chromium libraries.
Added some override files to make it work, the biggest of which defines
NewPermanentCallback() overrides that base/callback.h doesn't handle.
BUG=
34646
TEST=added unittests
Committed:
http://src.chromium.org/viewvc/chrome?view=rev&revision=45412