Create LayoutShiftAttribution objects in LayoutShiftTracker. Also mark the REF "experimental", so that it is tested, and add a test. Bug: 1053510 Change-Id: I8bac9c8002d20991599a1bf396f28dd9101b0f63 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2157988 Reviewed-by: Nicolás Peña Moreno <npm@chromium.org> Commit-Queue: Steve Kobes <skobes@chromium.org> Cr-Commit-Position: refs/heads/master@{#762442} diff --git a/layout-instability/resources/util.js b/layout-instability/resources/util.js index 515914e..2ef971d 100644 --- a/layout-instability/resources/util.js +++ b/layout-instability/resources/util.js
@@ -59,6 +59,7 @@ resetPromise(); const observer = new PerformanceObserver(list => { list.getEntries().forEach(entry => { + this.lastEntry = entry; this.score += entry.value; if (!entry.hadRecentInput) this.scoreWithInputExclusion += entry.value; diff --git a/layout-instability/sources.html b/layout-instability/sources.html new file mode 100644 index 0000000..599a5c4 --- /dev/null +++ b/layout-instability/sources.html
@@ -0,0 +1,38 @@ +<!DOCTYPE html> +<title>Layout Instability: sources attribute</title> +<link rel="help" href="https://wicg.github.io/layout-instability/" /> +<style> + +body { margin: 10px; } +#shifter { position: relative; width: 300px; height: 100px; } + +</style> +<div id="shifter"></div> +<script src="/resources/testharness.js"></script> +<script src="/resources/testharnessreport.js"></script> +<script src="resources/util.js"></script> +<script> + +strrect = r => `[${r.x},${r.y},${r.width},${r.height}]`; + +promise_test(async () => { + const watcher = new ScoreWatcher; + const shifter = document.querySelector("#shifter"); + + // Wait for the initial render to complete. + await waitForAnimationFrames(2); + + // Modify the position of the div. + shifter.style = "top: 60px; left: 10px"; + await watcher.promise; + + const sources = watcher.lastEntry.sources; + assert_equals(sources.length, 1); + + const source = sources[0]; + assert_equals(source.node, shifter); + assert_equals(strrect(source.previousRect), "[10,10,300,100]"); + assert_equals(strrect(source.currentRect), "[20,70,300,100]"); +}, "Sources attribute."); + +</script> 