Yes. c#0 is correct.
Would you describe more about the intended use case of the metric?

The metric is just intended to give high level insight into the amount of time web pages are blocked on loading scripts, to help understand where page load delays come from.

An extension of this metric tracks parser blocking time for doc.written scripts, which is important for the doc.write blocking intervention.

I looked at XMLDocumentParser and it looks like it tracks the pending script directly. Seems like it should be straightforward to instrument that class. Does that sound right to you?

Though this is filed in the parser component, I see it more as a page load metrics bug. I'll assign this to myself for now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4066a12bab519a1bb7afd04e0a1499c549bd491b

commit 4066a12bab519a1bb7afd04e0a1499c549bd491b
Author: bmcquade <bmcquade@chromium.org>
Date: Fri Aug 12 19:59:04 2016

Track parse time blocked on script in xml documents.

This adds the existing equivalent logic from HTMLDocumentParser to
XMLDocumentParser.

BUG= 632343 

Review-Url: https://codereview.chromium.org/2235733004
Cr-Commit-Position: refs/heads/master@{#411745}

[modify] https://crrev.com/4066a12bab519a1bb7afd04e0a1499c549bd491b/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp
[modify] https://crrev.com/4066a12bab519a1bb7afd04e0a1499c549bd491b/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.h