Revert "Revert "Simplify calling loopers""

This reverts commit 1edec352.

Previous attempt at this mistakenly used a pointer to an rvalue,
which was out of scope when it was used.

e.g.
    const SkPaint* sk_paint = filterBitmap(paint);
    ...
    // now use sk_paint <-- bad

Test: make

Bug: 178700363
Change-Id: I2e2913385e05257c482a5d12eaeaddadd04126e2