Log operator code histogram on new metric log

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 cfc3581269a74d8072089cca7303e4b63d669602..d430a053f540d6d426b78be4b7282816bf131264 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -10692,9 +10692,20 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <owner>marq@google.com</owner>
   <summary>
     The MCC (mobile country code) and MNC (mobile network code) of the network
-    operator when the network connection is changed to a mobile network. Value
-    zero means the connection is changed to a non-mobile network or the operator
-    code is unknown.
+    operator when the network connection is changed to a mobile network. A value
+    of zero means the connection is changed to a non-mobile network or the
+    operator code is unknown.
+  </summary>
+</histogram>
+
+<histogram name="NCN.NetworkOperatorMCCMNC_NewMetricsLog">
+  <owner>bolian@chromium.org</owner>
+  <owner>bengr@google.com</owner>
+  <owner>marq@google.com</owner>
+  <summary>
+    The MCC (mobile country code) and MNC (mobile network code) of the network
+    operator when a new metrics log is created. A value of zero means the
+    connection is a non-mobile network or the operator code is unknown.
   </summary>
 </histogram>