Add UMA to understand the typical total size of ServiceWorker script [2/2 chromium]

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index ede5029ff09e33dd2c2239959fedd13ca50a88ef..0d366d6898779e1c6ac009f4a95e5155adc31b1b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -34492,6 +34492,23 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="ServiceWorker.ScriptCachedMetadataTotalSize" units="bytes">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    The total length of cached metadata of Service Worker scripts. Logged on
+    each start of Service Worker only when the cached metadata is available. It
+    includes the main script and imported scripts.
+  </summary>
+</histogram>
+
+<histogram name="ServiceWorker.ScriptCount" units="count">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    The counts of scripts per Service Worker. Logged on each start of Service
+    Worker. It includes the main script and imported scripts.
+  </summary>
+</histogram>
+
 <histogram name="ServiceWorker.ScriptSize" units="bytes">
   <owner>ksakamoto@chromium.org</owner>
   <summary>
@@ -34500,6 +34517,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="ServiceWorker.ScriptTotalSize" units="bytes">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    The total length of Service Worker scripts. Logged on each start of Service
+    Worker. It includes the main script and imported scripts.
+  </summary>
+</histogram>
+
 <histogram name="ServiceWorker.StartWorker.Status"
     units="ServiceWorkerStatusCode">
   <owner>falken@chromium.org</owner>