Clean up any left over browser processes in the RecreateSKPs buildstep.
Clean up any left over browser processes in the RecreateSKPs buildstep.

BUG=skia:2055
R=borenet@google.com

Review URL: https://codereview.chromium.org/140003003

google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot