code: public void removeItemDecoration(ItemDecoration decor) {
          mItemDecorations.remove(decor);
          if (mItemDecorations.isEmpty()) {
              setWillNotDraw(ViewCompat.getOverScrollMode(this) == ViewCompat.OVER_SCROLL_NEVER);
          }
          markItemDecorInsetsDirty();
          requestLayout();
      }
docs: Remove an {@link com.twotoasters.android.support.v7.widget.RecyclerView.ItemDecoration} from this RecyclerView.
  
  <p>The given decoration will no longer impact the measurement and drawing of
  item views.</p>
  
  @param decor Decoration to remove
  @see #addItemDecoration(com.twotoasters.android.support.v7.widget.RecyclerView.ItemDecoration)