Moved sb_social_share_event_save() to sb_social.module and moved DB-handling logic out of it, into a new sb_social_share_save() function in sb_social.db.inc. See discussion: https://github.com/JacksonRiver/springboard_modules/commit/7038b179d0911cb65349b83bbc72f914d26adc34#commitcomment-7180126
Restored hook_sb_social_share_event_save() -- now part of sb_social_share_save() -- for the sake of legacy implementations.