After doing some survey on /dev/pstore on existing chromium issues, and referring to the crash collector of the chromiumos autotest framework, I think two files can be added to our crash report during the factory flow:
1. /dev/pstore/console-ramoops
2. /sys/kernel/debug/dri/0/i915_error_state (on Intel systems only)

One can refer to https://chromium-review.googlesource.com/c/195448, which added these two files to the crash collector in the autotest framework.

A draft for the modification is here: https://chromium-review.googlesource.com/c/611846

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/factory/+/e203d605c9da745a20a85fbdebca5f5fcb87411f

commit e203d605c9da745a20a85fbdebca5f5fcb87411f
Author: Shen-En Shih <petershih@chromium.org>
Date: Fri Aug 11 15:36:12 2017

utils: Collect pstore and i915 in crash collector

Collect console-ramoops and i915_error_state in the
crash info collector.

BUG= chromium:731007 
TEST=make test
TEST=manually test on a Chromebook

Change-Id: I18d08793d9d61e8d4480a5ffde7fb3145d2d489a
Reviewed-on: https://chromium-review.googlesource.com/611846
Commit-Ready: Shen-En Shih <petershih@chromium.org>
Tested-by: Shen-En Shih <petershih@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

[modify] https://crrev.com/e203d605c9da745a20a85fbdebca5f5fcb87411f/py/utils/sys_utils.py