fix(raf): test for undefined raf
fix(raf): test for undefined raf

When in a headless environment RAF may not be defined so we need to return the polyfilled version rather than letting the undefined function be called.
dennybiasiolli/ionic,AbraaoAlves/ionic,driftyco/ionic,jarrodkoch/ionic,manucorporat/ionic,manucorporat/ionic,cambronjay/ionic,jhlee8804/ionic,jarrodkoch/ionic,driftyco/ionic,driftyco/ionic,driftyco/ionic,AbraaoAlves/ionic,TillaTheHun0/ionic,joshesp/ionic,AbraaoAlves/ionic,alan-agius4/ionic,alan-agius4/ionic,jarrodkoch/ionic,jarrodkoch/ionic,joshesp/ionic,jhlee8804/ionic,joshesp/ionic,alan-agius4/ionic,janglednerves/ionic,jhlee8804/ionic,janglednerves/ionic,TillaTheHun0/ionic,TillaTheHun0/ionic,jhlee8804/ionic,dennybiasiolli/ionic,manucorporat/ionic,AbraaoAlves/ionic,dennybiasiolli/ionic,driftyco/ionic,brianespinosa/ionic2-sass,cambronjay/ionic,alan-agius4/ionic,joshesp/ionic,dennybiasiolli/ionic,janglednerves/ionic,jhlee8804/ionic,cambronjay/ionic,alan-agius4/ionic,cambronjay/ionic,TillaTheHun0/ionic,manucorporat/ionic,janglednerves/ionic,AbraaoAlves/ionic,cambronjay/ionic,jarrodkoch/ionic,dennybiasiolli/ionic,janglednerves/ionic,manucorporat/ionic,alan-agius4/ionic