503       row_(region.rows_.begin()),  in Iterator()
506     assert(row_->second->spans.size() > 0);  in Iterator()
507     row_span_ = row_->second->spans.begin();  in Iterator()
515   return row_ == region_.rows_.end();  in IsAtEnd()
523     if (row_span_ == row_->second->spans.end()) {  in Advance()
524       previous_row_ = row_;  in Advance()
525       ++row_;  in Advance()
526       if (row_ != region_.rows_.end()) {  in Advance()
527         assert(row_->second->spans.size() > 0);  in Advance()
528         row_span_ = row_->second->spans.begin();  in Advance()
539         previous_row_->second->bottom == row_->second->top &&  in Advance()
554   Rows::const_iterator bottom_row = row_;  in UpdateCurrentRect()
563   rect_ = DesktopRect::MakeLTRB(row_span_->left, row_->second->top,  in UpdateCurrentRect()