From cc6e2ffdbf3988f5af374685f4d84ad471c67009 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20Qu=C3=A8ze?= <florian@queze.net>
Date: Tue, 8 Apr 2025 08:42:01 +0000
Subject: [PATCH] Bug 1956726 - Migrate histograms to use Glean APIs for
 REL_PRELOAD_MISS_RATIO, r=chutten,necko-reviewers,sunil.

Differential Revision: https://phabricator.services.mozilla.com/D244294
---
 netwerk/metrics.yaml                | 39 +++++++++++++++++++++++++++++
 uriloader/preload/PreloaderBase.cpp |  6 ++---
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/netwerk/metrics.yaml b/netwerk/metrics.yaml
index 224b088806ee..92c89900026e 100644
--- a/netwerk/metrics.yaml
+++ b/netwerk/metrics.yaml
@@ -3168,3 +3168,42 @@ network:
       - necko@mozilla.com
     expires: never
     telemetry_mirror: IPV4_AND_IPV6_ADDRESS_CONNECTIVITY
+
+  rel_preload_miss_ratio:
+    type: labeled_counter
+    description: >
+      Ratio of used and unused resources preloaded with link rel=preload tag or
+      response header, broken down by supported resource type.
+
+      This metric was generated to correspond to the Legacy Telemetry
+      categorical histogram REL_PRELOAD_MISS_RATIO.
+    labels:
+      - TYPE_SCRIPT_USED
+      - TYPE_SCRIPT_UNUSED
+      - TYPE_STYLE_USED
+      - TYPE_STYLE_UNUSED
+      - TYPE_IMAGE_USED
+      - TYPE_IMAGE_UNUSED
+      - TYPE_FONT_USED
+      - TYPE_FONT_UNUSED
+      - TYPE_FETCH_USED
+      - TYPE_FETCH_UNUSED
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1658532
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1583604
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1666981
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1700831
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1736687
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1777403
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1658532
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1583604
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1666981
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1700831
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1736687
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1777403
+    notification_emails:
+      - necko@mozilla.com
+      - kershaw@mozilla.com
+    expires: never
+    telemetry_mirror: h#REL_PRELOAD_MISS_RATIO
diff --git a/uriloader/preload/PreloaderBase.cpp b/uriloader/preload/PreloaderBase.cpp
index 9ae2f85a0f6b..5e4b386e51fc 100644
--- a/uriloader/preload/PreloaderBase.cpp
+++ b/uriloader/preload/PreloaderBase.cpp
@@ -5,7 +5,7 @@
 #include "PreloaderBase.h"
 
 #include "mozilla/dom/Document.h"
-#include "mozilla/Telemetry.h"
+#include "mozilla/glean/NetwerkMetrics.h"
 #include "nsContentUtils.h"
 #include "nsIAsyncVerifyRedirectCallback.h"
 #include "nsIHttpChannel.h"
@@ -322,8 +322,8 @@ void PreloaderBase::ReportUsageTelemetry() {
     ++index;
   }
 
-  auto label = static_cast<Telemetry::LABELS_REL_PRELOAD_MISS_RATIO>(index);
-  Telemetry::AccumulateCategorical(label);
+  auto label = static_cast<glean::network::RelPreloadMissRatioLabel>(index);
+  glean::network::rel_preload_miss_ratio.EnumGet(label).Add();
 }
 
 nsresult PreloaderBase::AsyncConsume(nsIStreamListener* aListener) {