Browser: Chrome/58.0.3029.81
OS: reproduced on Windows NT 6.1, Ubuntu 14.04

Steps to reproduce:
- create an HTML file like:
<iframe src="https://spreadsheets.google.com/spreadsheet/loadredirect?authuser=0&amp;chrome=false&amp;gid=1&amp;key=121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4&amp;output=html&amp;pubredirect=true&amp;widget=true" width="100%" height="300" ></iframe>
- open it in Chrome (no need to be signed in, the spreadsheet is shared with anybody with the link)

Expected result
- The iframe displays

Actual result
- Its stays blank. No error in the JS console. The loading indicator keeps spinning.


Other info
- Issue reproduces on a classic Google Site. They probably created this page some time ago, as now the way to embed a sheet is to use /htmlembed directly.
- No problem in Firefox or Internet Explorer
- Seems to be linked with Chrome update to 58
- No problem with other ways of embedding:
iframe with pubhtml like in Sheets - File - publish: <br>
<iframe src="https://docs.google.com/a/google.com/spreadsheets/d/121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4/pubhtml?widget=true&amp;headers=false" width="100%" height="300"></iframe>
iframe with htmlembed like in Sites - Insert - spreadsheet: <br>
<iframe src="https://docs.google.com/spreadsheets/d/121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4/htmlembed?authuser=0" width="100%" height="300" frameborder="0" id="1865547276"></iframe>
- looking at the HTTP requests when reproducing, there are 2 redirections, and then the request that actually contains the content is 
https://docs.google.com/spreadsheets/d/121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4/htmlembed?chrome=false&gid=1&pubredirect=true&widget=true"
but it never finishes
- a net-internal capture (took from an incognito window while not signed-in, no problem with sharing) seems to suggest that chrome did receive an answer from docs.google.com:

t= 9547 [st= 399]        HTTP_TRANSACTION_HTTP2_SEND_REQUEST_HEADERS
                         --> :authority: docs.google.com
                             :method: GET
                             :path: /spreadsheets/d/121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4/htmlembed?chrome=false&gid=1&pubredirect=true&widget=true
                             :scheme: https
                             accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
                             accept-encoding: gzip, deflate, sdch, br
                             accept-language: en-US,en;q=0.8
                             cookie: NID=102=IMNBwTiLSzOdbf0-e0GHlKjDG_qGK3h7dibEj5XvTfpOf5BB5yHh3Eu9EC5OyDneSRZJdom-1eDvvqTKukyez1rsCksVVdAh7iK5vEEyOzOFnOC_BrlC2MM5MRBBq_8S
                             upgrade-insecure-requests: 1
                             user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36
t= 9547 [st= 399]     -HTTP_TRANSACTION_SEND_REQUEST
t= 9547 [st= 399]     +HTTP_TRANSACTION_READ_HEADERS  [dt=399]
t= 9946 [st= 798]        HTTP_TRANSACTION_READ_RESPONSE_HEADERS
                         --> HTTP/1.1 200
                             status: 200
                             content-type: text/html; charset=utf-8
                             x-robots-tag: noindex, nofollow, nosnippet
                             cache-control: no-cache, no-store, max-age=0, must-revalidate
                             pragma: no-cache
                             expires: Mon, 01 Jan 1990 00:00:00 GMT
                             date: Thu, 27 Apr 2017 15:36:49 GMT
                             content-encoding: gzip
                             x-content-type-options: nosniff
                             x-xss-protection: 1; mode=block
                             server: GSE
                             set-cookie: S=apps-spreadsheets=FKYWwf8jsT7LcpFlFTi_wTvYJw4pfNjJ; Domain=.docs.google.com; Expires=Thu, 27-Apr-2017 16:36:49 GMT; Path=/spreadsheets/d/121-IIl_E-e0S0CXYCk5-uF3C1S-GIWfvTW-5K-8zjy4; Secure; HttpOnly; Priority=LOW
                             alt-svc: quic=":443"; ma=2592000; v="37,36,35"

But it's not displayed.
 

Deleted: chrome-net-export-log.json 537 KB

chrome-net-export-log.json 537 KB View Download