refactor btoa/atob polyfill to work better with the compiler, and fewer boolean params
refactor btoa/atob polyfill to work better with the compiler, and fewer
boolean params


Former-commit-id: e4c79fbd65d5b7c39594c50c7c5a600784e16cc5 [formerly 31ed8794ced135226c757c99fdf22ca3c060328d]
Former-commit-id: eeb019eb4328a5a075060e895d77e63b90701d4f
romancow/Sugar,andrewplummer/Sugar,romancow/Sugar,andrewplummer/Sugar