Fix GN build for components/session_manager and /chromeos

BUG=None
TEST=user_manager GN ninja build (debug|official; is_component_build=yes|no)
TBR=oshima

Review URL: https://codereview.chromium.org/880203003

Cr-Commit-Position: refs/heads/master@{#313479}
2 files changed