Battery Status API: add UMA logging for Linux.

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 5ed014f3764c42a252eb1ebe3dd006138aefa7a6..dcaf1b30426659f883a200c9498241fd05191c49 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -1927,6 +1927,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="BatteryStatus.NumberBatteriesLinux"
+    enum="BatteryStatus.NumberBatteriesType">
+  <owner>timvolodine@chromium.org</owner>
+  <summary>
+    Number of batteries reported by the UPower service on Linux at the start of
+    the Battery Status API.
+  </summary>
+</histogram>
+
 <histogram name="BatteryStatus.StartAndroid" enum="BooleanSuccess">
   <owner>timvolodine@chromium.org</owner>
   <summary>
@@ -37614,6 +37623,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="2" label="Bad"/>
 </enum>
 
+<enum name="BatteryStatus.NumberBatteriesType" type="int">
+  <int value="0" label="No battery"/>
+  <int value="1" label="One battery"/>
+  <int value="2" label="Two batteries"/>
+  <int value="3" label="Three batteries"/>
+  <int value="4" label="Four batteries"/>
+  <int value="5" label="Five or more batteries"/>
+</enum>
+
 <enum name="BlacklistSetup" type="int">
   <int value="0" label="Blacklist enabled"/>
   <int value="1" label="Blacklist ran successfully."/>