1483394 - Remove unneeded #includes of nsContentUtils.h in /layout

Status: RESOLVED FIXED

(Core :: Layout, enhancement, P4)

Description

[Daniel Holbert [:dholbert]]

I watched an intern presentation today about finding the files in mozilla-central for which changes are the most expensive.

(where "expensive" = $DOWNSTREAM-FILES x $CHANGE-FREQUENCY)

nsContentUtils.h was towards the top.

As it happens, we have lots of includes of this file which are probably unneeded (based on the rough heuristic that the #include line for "nsContentUtils.h" is the only usage of the word nsContentUtils in the file).

Let's get rid of these likely-unnecessary #includes where possible, to reduce $DOWNSTREAM-FILES and make incremental builds faster when nsContentUtils.h changes (as it does frequently).

Comment 1

[Daniel Holbert [:dholbert]]

Here's the search I'm using to get my list of candidate files:
https://searchfox.org/mozilla-central/search?q=nsContentUtils&path=layout%2F

I'm skimming that list for entries where #include is the only thing.  (And I'm also doing a sanity-check for "scriptblocker" when editing the files, because nsAutoScriptBlocker is probably the most commonly-used thing that is *not* in the nsContentUtils namespace which is exported by nsContentUtils.h.)

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: Bug 1483394: Remove unneeded #includes of nsContentUtils.h in /layout. r?TYLin

For each file touched in this patch, thee file had an #include for
nsContentUtils.h, but no other mentions of the string "nsContentUtils", nor any
mention of its "ScriptBlocker"-related types. So these files likely don't need
their nsContentUtils.h include anymore, and we can remove it to get a marginal
win on build time/complexity.

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: screenshot of slide with top 10 most expensive files to change (nsContentUtils.h is #5)

(In reply to Daniel Holbert [:dholbert] from comment #0)
> I watched an intern presentation today about finding the files in
> mozilla-central for which changes are the most expensive.

(FWIW, this project is tracked in bug 1474442 & related bugs. I'm attaching a screenshot of the slide with the "most expensive files" as judged by this tool/analysis. nsContentUtils.h is the 5th-most-expensive file to change, according to this ranking.)

Comment 4

[Ting-Yu Lin [:TYLin] (PST, UTC-7)]

Comment on attachment 9000112 [details]
Bug 1483394: Remove unneeded #includes of nsContentUtils.h in /layout. r?TYLin

Ting-Yu Lin [:TYLin] (UTC-7) has approved the revision.

Comment 5

[Daniel Holbert [:dholbert]]

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=b93f30ff4472917f92ad9e706dc554df3fa2edd0

The reds there seem unrelated. Gonna go ahead and land.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/68faa8b52f60
Remove unneeded #includes of nsContentUtils.h in /layout. r=TYLin

Comment 7

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/68faa8b52f60