Track printer protocol usage for CUPS printers.

chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc

Index: chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc
diff --git a/chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc b/chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc
index a26a8bbc8891c4cd1e3d8b6760c6c7b3800598de..5783f0b498568290aa4c5f2abce49a57656c2975 100644
--- a/chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc
+++ b/chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.cc
@@ -11,6 +11,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/task_scheduler/post_task.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/printing/cups_print_job_manager.h"
@@ -123,6 +124,11 @@ class PrinterBackendProxyChromeos : public PrinterBackendProxy {
       return;
     }
 
+    // Log printer configuration for selected printer.
+    UMA_HISTOGRAM_ENUMERATION("Printing.CUPS.ProtocolUsed",
+                              printer->GetProtocol(),
+                              chromeos::Printer::PROTOCOL_MAX);
+
     if (prefs_->IsConfigurationCurrent(*printer)) {
       // Skip setup if the printer is already installed.
       HandlePrinterSetup(std::move(printer), cb, chromeos::SUCCESS);