If you focus on the password field and then hold down a letter key for 20+ minutes, the OS seems to continue accepting input forever instead of limiting the amount of text allowed in the field.  After a sufficiently long time has passed, it will log a couple of errors in UI.latest:

[1180:1180:1211/093018.236170:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 104 is too big.
[1180:1180:1211/093025.138359:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 120 is too big.
[1180:1180:1211/093033.355809:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 140 is too big.
[1180:1180:1211/093043.235260:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 166 is too big.
[1180:1180:1211/093055.616468:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 204 is too big.
[1180:1180:1211/093111.635333:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 256 is too big.
[1180:1180:1211/093133.322479:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 334 is too big.
[1180:1180:1211/093204.455046:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 460 is too big.
[1180:1180:1211/093252.385403:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 666 is too big.
[1180:1180:1211/093418.076236:ERROR:latency_info.cc(158)] RenderWidgetHostImpl::OnSwapCompositorFrame, LatencyInfo vector size 1044 is too big.

After this point, the system menu still works but other UI widgets (guest mode, shut down, navigating in the password field) seem to be stuck.