Bug 1927093 - Migrate scalars to use Glean APIs for script.preloader.mainthread_recompile, r=chutten.

Depends on D228300

Differential Revision: https://phabricator.services.mozilla.com/D228301

js/xpconnect/loader/ScriptPreloader.cpp

@@ -23,6 +23,7 @@
 #include "mozilla/Services.h"
 #include "mozilla/StaticPrefs_javascript.h"
 #include "mozilla/TaskController.h"
+#include "mozilla/glean/GleanMetrics.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/Try.h"
 #include "mozilla/Unused.h"
@@ -1001,8 +1002,7 @@ already_AddRefed<JS::Stencil> ScriptPreloader::WaitForCachedStencil(
         LOG(Info, "Script is small enough to recompile on main thread\n");
 
         script->mReadyToExecute = true;
-        Telemetry::ScalarAdd(
-            Telemetry::ScalarID::SCRIPT_PRELOADER_MAINTHREAD_RECOMPILE, 1);
+        glean::script_preloader::mainthread_recompile.Add(1);
       } else {
         LOG(Info, "Must wait for async script load: %s\n", script->mURL.get());
         auto start = TimeStamp::Now();

js/xpconnect/metrics.yaml

@@ -254,3 +254,31 @@ slow_script_warning:
     telemetry_mirror: Slow_script_warning_Shown_Content
     no_lint:
       - COMMON_PREFIX
+
+script.preloader:
+  mainthread_recompile:
+    type: counter
+    description: >
+      How many times we ended up recompiling a script from the script
+      preloader on the main thread.
+      This metric was generated to correspond to the Legacy Telemetry
+      scalar script.preloader.mainthread_recompile.
+    bugs:
+      - https://bugzil.la/1364235
+      - https://bugzil.la/1590385
+      - https://bugzil.la/1623098
+      - https://bugzil.la/1649954
+      - https://bugzil.la/1689257
+      - https://bugzil.la/1754639
+    data_reviews:
+      - https://bugzil.la/1364235
+      - https://bugzil.la/1590385
+      - https://bugzil.la/1623098
+      - https://bugzil.la/1649954
+      - https://bugzil.la/1689257
+      - https://bugzil.la/1754639
+    notification_emails:
+      - dothayer@mozilla.com
+      - plawless@mozilla.com
+    expires: never
+    telemetry_mirror: SCRIPT_PRELOADER_MAINTHREAD_RECOMPILE