Investing in Tomorrow's Workforce Act of 2019 This bill (1) directs the Government Accountability Office to study the barriers to providing, and opportunities for improving, training for workers in industries that have, or are likely to have, high rates of job loss due to automation; (2) directs the Department of Labor to award grants to eligible partnerships to support demonstration and pilot projects relating to the training needs of workers who are, or are likely to become, dislocated workers as a result of automation; (3) expands training programs for such workers, including activities that prepare the individuals for occupations in the technology sector; (4) authorizes the award of national dislocated worker grants to provide employment and training assistance to workers affected by advances in automation technology; and (5) expands funding for national dislocated worker grants.