Switch runtime flag ReportEventTimingAtVisibilityChange to stable

This is to launch feature ReportEventTimingAtVisibilityChange.
This CL does
1, add changelog.
2, switch runtime flag.
3, delete fieldtrial test config.

Bug: 374793631, 40879225
Change-Id: Idab9c88738b48c7d676b06b2ca0fb853e3794506
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5958769
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Hao Liu <haoliuk@chromium.org>
Reviewed-by: Michal Mocny <mmocny@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1373456}

docs/speed/metrics_changelog/2024_10_inp.md

@@ -0,0 +1,30 @@
+# Interaction to Next Paint Changes in Chrome 130
+
+## Enable ReportEventTimingAtVisibilityChange by default
+
+This feature is to report all interactions a user has with a webpage that are
+still in the middle of measurement right before the page closes or becomes
+hidden, at the page visibility change time. The situation is most common when
+the final interaction navigates the page away before next paint.
+
+As a result, a registered PerformanceObserver might not have time to call the
+observer callback with the final entries, but web developer can use
+.takeRecords() to synchronously read the final values.
+
+Note: this experiment was first landed in Chrome 128:
+[Reland "Flush event timings at visibility change"](https://chromium-review.googlesource.com/c/chromium/src/+/5704556), and was slowly rolled out.
+
+## How does this affect a site's metrics?
+
+Some sites will now report more interactions per pageload.
+In particular, some pages which did not have a chance to report even a single
+interaction (because document unloaded too quickly), might now report 1
+interaction.
+While we did not see statistically significant movements to INP
+scores with this change, we did see increased reporting coverage for the INP
+metric.
+
+## When were users affected?
+
+Launch was the week of Oct 21, 2024, when m130 was in stable, but a limited
+number of early adopters might have seen this change as early as m128.

docs/speed/metrics_changelog/inp.md

@@ -2,6 +2,9 @@
 
 This is a list of changes to [Interaction to Next Paint](https://web.dev/inp).
 
+
+* Chrome 130
+  * Launch feature: [Enable ReportEventTimingAtVisibilityChange by default](2024_10_inp.md)
 * Chrome 129
   * Launch feature: [Enable ContinueEventTimingRecordingWhenBufferIsFull by default](2024_09_inp.md)
 * Chrome 128

testing/variations/fieldtrial_testing_config.json

@@ -19812,25 +19812,22 @@
             ]
         }
     ],
-    "ReportEventTimingAtVisibilityChange": [
+    "ReportCertificateErrors": [
         {
             "platforms": [
                 "android",
                 "chromeos",
-                "chromeos_lacros",
                 "fuchsia",
                 "linux",
                 "mac",
-                "windows",
-                "android_webview",
-                "android_weblayer"
+                "windows"
             ],
             "experiments": [
                 {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "ReportEventTimingAtVisibilityChange"
-                    ]
+                    "name": "ShowAndPossiblySend",
+                    "params": {
+                        "sendingThreshold": "1.0"
+                    }
                 }
             ]
         }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -3552,7 +3552,7 @@
     },
     {
       name: "ReportEventTimingAtVisibilityChange",
-      status: "experimental",
+      status: "stable",
     },
     {
       // TODO(crbug.com/1500633): Remove this flag when the new CursorAnchorInfo