/**
 * If your view subclass is displaying its own Drawable objects, it should
 * override this function and return true for any Drawable it is
 * displaying.  This allows animations for those drawables to be
 * scheduled.
 *
 * <p>Be sure to call through to the super class when overriding this
 * function.
 *
 * @param who The Drawable to verify.  Return true if it is one you are
 *            displaying, else return the result of calling through to the
 *            super class.
 *
 * @return boolean If true than the Drawable is being displayed in the
 *         view; else false and it is not allowed to animate.
 *
 * @see #unscheduleDrawable(android.graphics.drawable.Drawable)
 * @see #drawableStateChanged()
 */
@CallSuper
protected boolean verifyDrawable(Drawable who) {
    return who == mBackground || (mScrollCache != null && mScrollCache.scrollBar == who)
            || (mForegroundInfo != null && mForegroundInfo.mDrawable == who);
}