QueryMostVisitedURLsRequest 1422 chrome/browser/history/history_backend.cc     scoped_refptr<QueryMostVisitedURLsRequest> request,
QueryMostVisitedURLsRequest  186 chrome/browser/history/history_backend.h       scoped_refptr<QueryMostVisitedURLsRequest> request,
QueryMostVisitedURLsRequest  846 chrome/browser/history/history_service.cc                   new history::QueryMostVisitedURLsRequest(callback),