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 f174503312c9e67d7be4f9e580c69aa695c65182..d106e226e2fa7f4d675108d195c5fb86040469e6 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -48633,6 +48633,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Power.ConnectedChargingPorts" enum="PowerChargingPorts">
+  <owner>bleung@chromium.org</owner>
+  <owner>derat@chromium.org</owner>
+  <summary>
+    Connected charging ports on Chrome OS. A sample is reported every time that
+    the power manager polls sysfs (typically every 30 seconds). Ordinals are
+    assigned based on the lexicographical ordering of power supply names from
+    sysfs and have no implied correspondence with ports' physical locations. For
+    example, with ports 'CROS_USB_PD_CHARGER0' and 'CROS_USB_PD_CHARGER1',
+    'first' refers to the former and 'second' to the latter. To determine a
+    port's physical location, see the powerd charging_ports pref in the device's
+    overlay.
+  </summary>
+</histogram>
+
 <histogram name="Power.DarkResumeWakeDurationMs" units="ms">
   <owner>chirantan@chromium.org</owner>
   <summary>
@@ -100140,6 +100155,17 @@ value.
   <int value="4" label="Safe Spring Charger"/>
 </enum>
 
+<enum name="PowerChargingPorts" type="int">

[Daniel Erat, 2017/01/12 18:38:27]

would "PowerConnectedChargingPorts" be better? just "ConnectedChargingPorts"?

[Steven Holte, 2017/01/12 21:23:23]

PowerConnectedChargingPorts might be slightly better.

[Daniel Erat, 2017/01/13 02:03:45]

done. thanks!

+  <summary>
+    Connected charging ports on Chrome OS, as reported by the kernel.

[Daniel Erat, 2017/01/12 18:38:27]

i put the details about this enum inside of the histogram's summary instead of
here, as the former appears to be displayed on the dashboard while enums'
summaries aren't (unless i was looking in the wrong place).

[Steven Holte, 2017/01/12 21:23:23]

Yes, I don't think these are currently displayed, so putting it in the
histograms description seems fine.

+  </summary>
+  <int value="0" label="No ports connected"/>
+  <int value="1" label="First port connected"/>
+  <int value="2" label="Second port connected"/>
+  <int value="3" label="First and second ports connected"/>
+  <int value="4" label="More than two ports exist"/>
+</enum>
+
 <enum name="PowerSupplyType" type="int">
   <summary>
     The type of power supply connected to a Chrome OS system, as reported by the