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 8f48bcae1cfdff9337be32c5f00b5fca51b194ad..5fa71f2b42905028439c2a422d4eb384d503d76d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -52792,6 +52792,14 @@ 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>
@@ -102903,6 +102911,7 @@ To add a new entry, add it with any value and run test to compute valid value.
 </histogram_suffixes>
 
 <histogram_suffixes name="ServiceWorker.EventType">
+  <affected-histogram name="ServiceWorker.EventDispatchingDelay"/>
   <suffix name="ACTIVATE" label="ACTIVATE"/>
   <suffix name="INSTALL" label="INSTALL"/>
   <suffix name="SYNC" label="SYNC"/>
@@ -103044,7 +103053,11 @@ To add a new entry, add it with any value and run test to compute valid value.
 </histogram_suffixes>
 
 <histogram_suffixes name="ServiceWorkerSpecialApps" 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="PageLoad.Clients.ServiceWorker.DocumentTiming.NavigationToDOMContentLoadedEventFired"/>
   <affected-histogram
@@ -103053,6 +103066,32 @@ To add a new entry, add it with any value and run test to compute valid value.
       name="PageLoad.Clients.ServiceWorker.PaintTiming.NavigationToFirstContentfulPaint"/>
   <affected-histogram
       name="PageLoad.Clients.ServiceWorker.PaintTiming.ParseStartToFirstContentfulPaint"/>
+  <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">