Cast extension private API for ChromeOS system tray.

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 526cb57dbb41c4042c291f989aec1c4b980f1504..850ed922dc63fa15a7363945850f7b007eb7cf45 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -56173,6 +56173,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="373" label="WEB_VIEW_INTERNAL_ON_UNRESPONSIVE"/>
   <int value="374" label="WEB_VIEW_INTERNAL_ON_ZOOM_CHANGE"/>
   <int value="375" label="GUEST_VIEW_INTERNAL_ON_RESIZE"/>
+  <int value="376" label="CAST_DEVICES_PRIVATE_ON_UPDATE_DEVICES_REQUESTED"/>
+  <int value="377" label="CAST_DEVICES_PRIVATE_ON_START_CAST"/>
+  <int value="378" label="CAST_DEVICES_PRIVATE_ON_STOP_CAST"/>
 </enum>
 
 <enum name="ExtensionFileWriteResult" type="int">
@@ -57291,6 +57294,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1072" label="NETWORKINGPRIVATE_UNLOCKCELLULARSIM"/>
   <int value="1073" label="NETWORKINGPRIVATE_SETCELLULARSIMSTATE"/>
   <int value="1074" label="ENTERPRISE_DEVICEATTRIBUTES_GETDIRECTORYDEVICEID"/>
+  <int value="1075" label="CASTDEVICESPRIVATE_UPDATEDEVICES"/>
 </enum>
 
 <enum name="ExtensionInstallCause" type="int">