Mark virtual/softwarecompositing/plugins/webplugin*  for rebaseline.

TBR=jamesr
BUG=350578

Review URL: https://codereview.chromium.org/194703013

git-svn-id: svn://svn.chromium.org/blink/trunk@168952 bbb929c8-8fbe-4397-9dbb-9b2b20218538