fix typo in pipeline.cc
fix typo in pipeline.cc

TBR=bmeurer@chromium.org

BUG=

Review URL: https://codereview.chromium.org/743603003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#25413}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh