Measure elapsed time to check ServiceWorker allowed

To understand the cost to check if the ServiceWorker is allowed inside
`ServiceWorkerContainerHostForClient`, let me add a metrics for that.

Change-Id: I1aad423725e0aaaab35afd72b5ffdfa7fa0c6781
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6332354
Reviewed-by: Shunya Shishido <sisidovski@chromium.org>
Auto-Submit: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Commit-Queue: Shunya Shishido <sisidovski@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1428752}

content/browser/service_worker/service_worker_container_host.cc

@@ -727,6 +727,7 @@ bool ServiceWorkerContainerHostForClient::AllowServiceWorker(
   if (!browser_context) {
     return false;
   }
+  auto start_time = base::TimeTicks::Now();
   AllowServiceWorkerResult allowed =
       GetContentClient()->browser()->AllowServiceWorker(
           scope,
@@ -734,6 +735,9 @@ bool ServiceWorkerContainerHostForClient::AllowServiceWorker(
               service_worker_client().key()),
           service_worker_client().top_frame_origin(), script_url,
           browser_context);
+  base::UmaHistogramMicrosecondsTimes(
+      "ServiceWorker.ContainerHostForClient.AllowServiceWorkerCallTime",
+      base::TimeTicks::Now() - start_time);
   if (service_worker_client().IsContainerForWindowClient()) {
     auto* rfh = RenderFrameHostImpl::FromID(
         service_worker_client().GetRenderFrameHostId());

tools/metrics/histograms/metadata/service/histograms.xml

@@ -236,6 +236,21 @@ chromium-metrics-reviews@google.com.
   </summary>
 </histogram>
 
+<histogram
+    name="ServiceWorker.ContainerHostForClient.AllowServiceWorkerCallTime"
+    units="microseconds" expires_after="2025-09-06">
+  <owner>yyanagisawa@chromium.org</owner>
+  <owner>chrome-worker@google.com</owner>
+  <summary>
+    Time spent to check ServiceWorker allowed on the context. Recorded when
+    ServiceWorker is registered, updated, or deleted for non-ServiceWorker
+    client.
+
+    Note: The metrics is reported from all clients. Some of clients may not have
+    high resolution timer that can send metrics with microseconds precision.
+  </summary>
+</histogram>
+
 <histogram name="ServiceWorker.CorsExemptHeaderListSize" units="count"
     expires_after="2025-08-24">
   <owner>sisidovski@chromium.org</owner>