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 f01549cc4f4725adacd5e1d3b19e9c97220cec33..85d1a21d89a65cc39fbfcc045598455bac9037d3 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -39798,6 +39798,17 @@ 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
+    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>