It depends on the maturity of your users.
The scrollbar is good option to give your users a hint about the amount of content that is remaining to be viewed. By the size of the scroller handle. Showing it persistently need not be the case. As the user is interested in the content. This can appear when the user is swiping from left to right. And display scroll bar for the duration it scrolls. And once content stops sliding, it goes off.
The white part on right side is not good indicator that there is some more content. This affodance is also used to display that there is no more content. Remember the contact list, when at the extreme ends of the list, a soft color appears(with elastic animation) indicating no more items to display.
A better solution could be to have an arrow with the white patch and hide the horizontal scrollbar. This will indicate the scrollable area on right.
When the scrolling begins, same arrow with the white patch appears on left too. Indicating the content is available on both the sides.
And during the scroll, you may display the horizontal scroll bar which will send out indications of amount of content left. And the horizontal scroller disappears when scrolling stops.