Get rid of the old FlagRegisterer constructor.

R=jkline,georgevdd
DELTA=27  (0 added, 27 deleted, 0 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=3609


git-svn-id: https://gflags.googlecode.com/svn/trunk@69 6586e3c6-dcc4-952a-343f-ff74eb82781d