⚗️ [RUM-13259]Track action names in shadow dom

[rgaignault]

Motivation

Clicks inside Shadow DOM components currently result in imprecise action names because event.target is retargeted to the shadow host.

Changes

This PR adds experimental support for extracting accurate action names from elements inside Shadow DOM

• betaTrackActionsInShadowDom Enables action name extraction from Shadow DOM elements
• Uses event.composedPath() to get the actual clicked element

This is the first phase of Shadow DOM support, focusing on action names only. Selector tracking inside Shadow DOM will be added in a follow-up PR. This feature is experimental and gated behind the betaTrackActionsInShadowDom opt-in parameter.

Test instructions

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.

[cit-pr-commenter]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	164.34 KiB	164.90 KiB	+573 B	+0.34%	✅
Rum Profiler	4.32 KiB	4.32 KiB	0 B	0.00%	✅
Rum Recorder	20.03 KiB	20.03 KiB	0 B	0.00%	✅
Logs	56.14 KiB	56.14 KiB	0 B	0.00%	✅
Flagging	944 B	944 B	0 B	0.00%	✅
Rum Slim	121.62 KiB	122.21 KiB	+600 B	+0.48%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base CPU Time (ms)	Local CPU Time (ms)	𝚫%
RUM - add global context	0.0046	0.0066	+43.48%
RUM - add action	0.0132	0.019	+43.94%
RUM - add error	0.0145	0.0154	+6.21%
RUM - add timing	0.0028	0.0039	+39.29%
RUM - start view	0.0035	0.004	+14.29%
RUM - start/stop session replay recording	0.0007	0.0008	+14.29%
Logs - log message	0.0147	0.0162	+10.20%

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	25.63 KiB	25.97 KiB	+353 B
RUM - add action	49.22 KiB	51.07 KiB	+1.85 KiB
RUM - add timing	23.95 KiB	24.39 KiB	+449 B
RUM - add error	55.41 KiB	55.77 KiB	+364 B
RUM - start/stop session replay recording	23.60 KiB	23.77 KiB	+176 B
RUM - start view	423.90 KiB	421.14 KiB	-2.76 KiB
Logs - log message	44.35 KiB	45.22 KiB	+895 B

🔗 RealWorld

[datadog-official]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage
• Patch Coverage: 77.42%
• Overall Coverage: 77.22% (-0.02%)

View detailed report

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[BeltranBulbarellaDD]

Nice! Works perfectly with the html test you sent me.
Looks good in the explorer UI too

[amortemousque]

💬 suggestion: ‏Could be nice to also test privacy settings with shadow dom?

[rgaignault]

Good idea ! I added one 👍

[amortemousque]

💭 thought: I don’t think we need the beta prefix. IMO, the implementation is not too complex to justify it.
I recommend putting the feature behind a feature flag so we can easily enable or disable it during dogfooding.