Tested the issue on chrome version 65.0.3325.73 on Ubuntu 14.04 with steps mentioned below:
1) Launched chrome and navigated to URL: https://cvazac.netlify.com/tabs.html
2) Opened Devtools> Console and Devtools> Network and checked for the time field
3) In Devtools> Network tab, under time section observed 27ms 

@Reporter:
Please find the attached screenshot for your reference and let us know your inputs on it which helps us in further triaging it in better way.

Thanks!

Deleted: 798446.png 159 KB

	798446.png 159 KB View Download

Switch to the console and you will see the failing assert. 

If you evaluate this in the console, the value will be 0. It should be 123.
```
performance.getEntriesByType('resource')[0].serverTiming[0].duration
```

If you switch over to the network tab, you'll see that the response header is this:
```
server-timing: metric	;	dur	=	123	;
```

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

This looks extremely straight forward.

Deep, can you take a look?

http://jsonbin.org was a useful test example, but their header format is deprecated (as the console message mentions).  I have an internal test that adds the Server-Timing header (regrettably I can't expose it), but I get the output in dev tools (in screenshot illustrated as "pure_delay" = 506.5ms), but nothing in the resourceTiming entry (blank entry in serverTiming).

Since the previous release (macOS chrome 65), the values would appear in devTools, but no duration was included in the resourceTiming entry.  These current examples are from "66.0.3359.117 (Official Build)"

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	serverTimingIllustration.png 166 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5ec3a7338a79dc825bb2bde3efeeb056ff117f06

commit 5ec3a7338a79dc825bb2bde3efeeb056ff117f06
Author: Tom McKee <tommckee@chromium.org>
Date: Mon Jul 23 23:38:45 2018

Adding tests against and fixes for tabs in Server-Timing headers

According to the spec
(https://w3c.github.io/server-timing/#the-server-timing-header-field),
optional whitespace is allowed amongst parameter names and values. We
should be discarding this whitespace during parsing but, when there are
tabs, we were treating it like an error and discarding the whole value.

Changed the code that tokenizes HTTP headers to skip tabs and spaces
when consuming optional whitespace.

BUG= 798446 

Change-Id: If776761e5ea199e662ec7b2b5aa245e4581131fd
Reviewed-on: https://chromium-review.googlesource.com/1147258
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Tom McKee <tommckee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577325}
[add] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/resources/parsing/84.js
[add] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/resources/parsing/84.js.sub.headers
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/server_timing_header-parsing-expected.txt
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/server_timing_header-parsing.html
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/server_timing_header-parsing.https-expected.txt
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/WebKit/LayoutTests/external/wpt/server-timing/server_timing_header-parsing.https.html
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/blink/renderer/platform/network/header_field_tokenizer.cc
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/blink/renderer/platform/network/header_field_tokenizer.h
[modify] https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06/third_party/blink/renderer/platform/network/parsed_content_header_field_parameters_test.cc

Fixed in https://crrev.com/5ec3a7338a79dc825bb2bde3efeeb056ff117f06