am 2b3509c9: Merge change I51438c18 into eclair-mr2

Merge commit '2b3509c9a5d6f3a7142430cd0b81d135a9c0a5df' into eclair-mr2-plus-aosp

* commit '2b3509c9a5d6f3a7142430cd0b81d135a9c0a5df':
  the vertex index should be "first + i".