sync compositor: pass simple gfx types by const ref

See bug for reasoning

BUG=159273

Review URL: https://codereview.chromium.org/1417893006

Cr-Commit-Position: refs/heads/master@{#356653}
  SoftwareDevice(SynchronousCompositorOutputSurface* surface)
    : surface_(surface) {
  }

  SoftwareDevice(SynchronousCompositorOutputSurface* surface)
    : surface_(surface) {
  }
