Remove Extensions.NetworkDelayStartup histogram

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 edfe252772965e0350e02f6d75f453a54ef84ed6..a223b17e225d23fb80bffa9d0c97f590bd7e91b8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -15955,6 +15955,18 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Extensions.NetworkDelayStartup" units="ms">
+  <obsolete>
+    Never used. Added to source 06/2012. Removed from source and added here
+    09/2016.
+  </obsolete>
+  <owner>mpcomplete@chromium.org</owner>

[Devlin, 2016/09/14 15:01:15]

(in cl description)
but you should not ask him about it.

This seems to nullify the point of owners.  Additionally, I doubt anyone reading
the histograms.xml file will ever read the CL that added it to find out that you
shouldn't ask him about it.  I'll let holte@ have final say, but I'd suggest not
adding an owners tag for this (obsolete) histogram.

[Adam Rice, 2016/09/15 01:27:20]

I assumed that the <owner> tag was required. I have removed it.

+  <summary>
+    Delay of network requests due to waiting for extension declarativeWebRequest
+    rules to be loaded from disk at startup.
+  </summary>
+</histogram>
+
 <histogram name="Extensions.NonWebstoreLocation" enum="ExtensionLocation">
   <owner>rdevlin.cronin@chromium.org</owner>
   <summary>