chrome ToT on desktop at r502584

run chrome --mus --login-manager

See warnings:
[63754:63789:0918/142615.360927:ERROR:surface_aggregator.cc(207)] SurfaceId(FrameSinkId(2, 32), LocalSurfaceId(1, (90BC31713CB84FF2B60E6730F610CBBE)lu)) is missing during aggregation

The surface isn't in the surface manager:
SurfaceId(FrameSinkId(0, 0), LocalSurfaceId(1, (D4EB988EF12F6F6B6544786893A3038F)lu))
  SurfaceId(FrameSinkId(1, 2), LocalSurfaceId(1, (347F477D94FD13A7B6FB1DBF35D5293D)lu)) live active 1280x768
    SurfaceId(FrameSinkId(2, 1), LocalSurfaceId(1, (4F3536BEB1688BD82A61126A1DD39114)lu)) RootWindow-0 live pending 1280x768 active 1280x768

But it shows up later:
[63754:63789:0918/142615.977353:ERROR:surface_aggregator.cc(217)] JAMES SurfaceId(FrameSinkId(0, 0), LocalSurfaceId(1, (D4EB988EF12F6F6B6544786893A3038F)lu))
  SurfaceId(FrameSinkId(1, 2), LocalSurfaceId(1, (347F477D94FD13A7B6FB1DBF35D5293D)lu)) live active 1280x768
    SurfaceId(FrameSinkId(2, 1), LocalSurfaceId(1, (4F3536BEB1688BD82A61126A1DD39114)lu)) RootWindow-0 live active 1280x768
      SurfaceId(FrameSinkId(2, 32), LocalSurfaceId(1, (90BC31713CB84FF2B60E6730F610CBBE)lu)) RenderWidgetHostViewAura live active 1280x768

Maybe a race?