Run up to 8 iterations of Gauss-Newton, choose the best error

We're seeing profiles that really stress the limits of this
strategy, so we're probably going to have change our approach.
For now, this dramatically improves the results on the last
two profiles we've received via bug reports.

Bug: chromium:869115
Bug: chromium:1017960

Change-Id: I2565e3eb3f67d1e957ec6211f11d818f922c92d8
Reviewed-by: Mike Klein <>
Commit-Queue: Brian Osman <>
31 files changed