Add metrics to printer setup flow.

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 7de5ee9588f25c6f8f38940f6919a63cce2fdb85..1683ed69a6c9166c17573dce4ad21ba7a666e59d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -56540,6 +56540,32 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Printing.CUPS.PpdSource" enum="PpdSource">
+  <owner>skau@chromium.org</owner>
+  <summary>
+    The source of PostScript Printer Description files used during printer
+    setup.  Recorded when a printer is successfully configured.  Only recorded
+    on Chrome OS.
+  </summary>
+</histogram>
+
+<histogram name="Printing.CUPS.PrintersDiscovered" units="count">
+  <owner>skau@chromium.org</owner>
+  <summary>
+    The number of printers shown in the discovered printers dialog during
+    printer set up.  Only recorded on Chrome OS.
+  </summary>
+</histogram>
+
+<histogram name="Printing.CUPS.PrinterSetupResult" enum="PrinterSetupResult">
+  <owner>skau@chromium.org</owner>
+  <summary>
+    The success or error code for the set up of a CUPS printer.  Recorded when
+    set up is attempted through the settings dialogs.  Only recorded on Chrome
+    OS.
+  </summary>
+</histogram>
+
 <histogram name="PrintPreview.DestinationAction"
     enum="PrintPreviewPrintDestinationBuckets">
   <owner>vitalybuka@chromium.org</owner>