Introduce ServiceWorker.EventDispatchingDelay UMA

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 563005187a179030a20017780f96527ad09e1f8b..bc0af7db589475f6b91e6d09cc9eea24566f707a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -53177,6 +53177,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="ServiceWorker.EventDispatchingDelay" units="ms">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    The time taken between sending an event IPC from the browser process to a
+    Service Worker and executing the event handler in the Service Worker.
+  </summary>
+</histogram>
+
 <histogram name="ServiceWorker.EventHandledRatioType.Fetch"
     enum="ServiceWorkerEventHandleRatioType">
   <owner>kinuko@chromium.org</owner>
@@ -103488,6 +103496,7 @@ To add a new entry, add it with any value and run test to compute valid value.
       label="NAVIGATION_HINT_LINK_TAP_UNCONFIRMED"/>
   <suffix name="NAVIGATION_HINT_LINK_TAP_DOWN"
       label="NAVIGATION_HINT_LINK_TAP_DOWN"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay"/>
   <affected-histogram name="ServiceWorker.StartWorker.StatusByPurpose"/>
   <affected-histogram name="ServiceWorker.StartWorker.Time_DuringStartup"/>
   <affected-histogram name="ServiceWorker.StartWorker.Time_ExistingProcess"/>
@@ -103616,6 +103625,41 @@ To add a new entry, add it with any value and run test to compute valid value.
       name="PageLoad.Clients.ServiceWorker.PaintTiming.ParseStartToFirstContentfulPaint"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="ServiceWorkerSpecialAppsForEventDispatchingDelay"
+    separator=".">
+  <suffix name="docs" label="Custom histogram for Google Docs and Drive"/>
+  <suffix name="gmail" label="Custom histogram for GMail"/>
+  <suffix name="inbox" label="Custom histogram for Inbox"/>
+  <suffix name="ntp" label="Custom histogram for New Tab Page"/>
+  <suffix name="plus" label="Custom histogram for Google+"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_ACTIVATE"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_FETCH_MAIN_FRAME"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_FETCH_SHARED_WORKER"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_FETCH_SUB_FRAME"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_FETCH_SUB_RESOURCE"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_FOREIGN_FETCH"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_GEOFENCING"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_INSTALL"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_MESSAGE"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_NAVIGATION_HINT_LINK_MOUSE_DOWN"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_NAVIGATION_HINT_LINK_TAP_DOWN"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_NAVIGATION_HINT_LINK_TAP_UNCONFIRMED"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_NOTIFICATION_CLICK"/>
+  <affected-histogram
+      name="ServiceWorker.EventDispatchingDelay_NOTIFICATION_CLOSE"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_PUSH"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_SYNC"/>
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay_UNKNOWN"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="SessionRestoreTabCountMemoryPressure">
   <suffix name="MemoryPressure"
       label="Total tabs involved in session restore that encountered memory