Add missing user action in actions.xml.

Bug: 920663
Change-Id: Ieec35e703fe5fd0619c70c800879b0f8995afd8b
Reviewed-on: https://chromium-review.googlesource.com/c/1450021
Commit-Queue: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Auto-Submit: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629612}

tools/metrics/actions/actions.xml

@@ -19892,8 +19892,11 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="Tab.Screenshot.WithoutStoragePermission">
-  <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
-  <description>Please enter the description of the metric.</description>
+  <owner>sebsg@chromium.org</owner>
+  <description>
+    Recorded when the user takes a screenshot of a chrome tab when chrome
+    doesn't have storage permissions.
+  </description>
 </action>
 
 <action name="Tab_DropURLBetweenTabs">