code: @Override
      @TargetApi(Build.VERSION_CODES.LOLLIPOP)
      public void getOutline(@NonNull Outline outline) {
          final LayerState state = mLayerState;
          final ChildDrawable[] children = state.mChildren;
          final int N = state.mNum;
          for (int i = 0; i < N; i++) {
              if (children[i].mId != R.id.carbon_mask) {
                  children[i].mDrawable.getOutline(outline);
                  if (!outline.isEmpty()) return;
              }
          }
      }
docs: Populates <code>outline</code> with the first available layer outline, excluding the mask
  layer.
  
  @param outline Outline in which to place the first available layer outline