Refactor the ProfileSummaryInfo to use doInitialization and doFinalization to handle Module update.

Summary: This refactors the change in r282616

Reviewers: davidxl, eraman, mehdi_amini

Subscribers: mehdi_amini, davide, llvm-commits

Differential Revision: https://reviews.llvm.org/D25041

llvm-svn: 282630