code: void ensurePadding() {
          final int N = mLayerState.mNum;
          if (mPaddingL != null && mPaddingL.length >= N) {
              return;
          }
  
          mPaddingL = new int[N];
          mPaddingT = new int[N];
          mPaddingR = new int[N];
          mPaddingB = new int[N];
      }
docs: Ensures the child padding caches are large enough.