CHICAGO — Google has agreed to buy the soon-to-be-renovated James R. Thompson Center in heart of the Loop, a victory for Chicago’s central business district and for Illinois Gov. J.B. Pritzker as he seeks reelection and fends off criticism over recent high-profile corporate departures. Under the Google deal, announced at a Wednesday morning news conference in the soaring atrium of the Helmut Jahn-designed building, the state will be paid $30 million in cash and get the title to the former BMO Harris Bank headquarters at 115 S. LaSalle Street, valued at $75 million, which will become a state of…