Record difference between the maximum and minimum wireless signal strength

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 61c80867ccc36e452c2a53ae1235d6162a276de3..9584a06d7cff5bf6299492a021282a51879867b2 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -39822,6 +39822,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="NQE.CellularSignalStrengthDifference" units="dBm">
+  <owner>tbansal@chromium.org</owner>
+  <owner>bengr@chromium.org</owner>
+  <summary>
+    Difference between the minimum and the maximum received signal strength
+    since the last connection change event. Recorded only on cellular
+    connections on Android platform when the cellular signal strength was

[bengr, 2016/12/15 23:19:16]

on -> on the
was -> is

+    available. Recorded right before a connection change event.
+  </summary>
+</histogram>
+
 <histogram name="NQE.Correlation.ResourceLoadTime.0Kb_128Kb">
   <owner>tbansal@chromium.org</owner>
   <owner>bengr@chromium.org</owner>