Returns an Animator which can animate a clipping circle.
Any shadow cast by the View will respect the circular clip from this animator.
Only a single non-rectangular clip can be applied on a View at any time.
Views clipped by a circular reveal animation take priority over
{@link View#setClipToOutline(boolean) View Outline clipping}.
Note that the animation returned here is a one-shot animation. It cannot
be re-used, and once started it cannot be paused or resumed. It is also
an asynchronous animation that automatically runs off of the UI thread.
As a result {@link AnimatorListener#onAnimationEnd(Animator)}
will occur after the animation has ended, but it may be delayed depending
on thread responsiveness.
return new RevealAnimator(view, centerX, centerY, startRadius, endRadius);