Network Error Logging: Remove redundant `uri` field

Per https://github.com/w3c/network-error-logging/pull/90, a NEL report's
`url` field now contains the (sanitized) URL of the request that the
report describes.  (Before that spec update, it was supposed to contain
the URL of the page that made the request, which isn't relevant for
NEL.)  Now that the report contains the "right" URL, the NEL body's
`uri` field is redundant, and can be removed.

Bug: 748549
Change-Id: Ibd2b0213b829e94329ecc7263baecd549d41e40c
Reviewed-on: https://chromium-review.googlesource.com/1141271
Reviewed-by: Misha Efimov <mef@chromium.org>
Commit-Queue: Douglas Creager <dcreager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576312}
5 files changed