We can't use block when we have constrained space anymore. Use Flex instead.
We can't use block when we have constrained space anymore. Use Flex instead.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1230053005 .

jianglu/mojo,afandria/mojo,jianglu/mojo,jianglu/mojo,jianglu/mojo,afandria/mojo,jianglu/mojo,jianglu/mojo,jianglu/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,jianglu/mojo,afandria/mojo