Yup! I suspect, since I now know I am not the only one, that it must have been something they had changed overnight (06/07) by way of an upgrade. I wish they would give us the option because I am close to giving up on Chrome.
Yesterday I tried closing Chrome and rebooting but it remained the same.
This morning I went into settings and changed the 'On start-up' from 'Open the New Tab page' to 'Continue where you left off'. Closed Chrome and the frequently used pages were restored when I reopened it. I then went back into settings and resumed the button on 'Open the New Tab page'.
As I said I wish it would be possible to install the updates manually!