Split chrome_error_util into a second file, nserror_util.

chrome_error_util will contain EarlGrey-specific code, while generic
NSError generation will go in nserror_util.

Bug: 922813
Change-Id: Id9fcbd978e420956361cb0542e157020f6f33945
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1579469
Commit-Queue: ericale <ericale@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653677}
9 files changed