Log printer additions and removals by protocol.

chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc

Index: chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc
diff --git a/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc b/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc
index 28a1781f5cad216bd1123cd274008f7d44ca2c0e..c6e28eca3d8fbdf1ce327cfa726d3ae2d032758d 100644
--- a/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc
+++ b/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.cc
@@ -11,6 +11,7 @@
 #include "base/files/file_util.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/strings/string_util.h"
 #include "base/threading/sequenced_task_runner_handle.h"
@@ -44,7 +45,12 @@ namespace settings {
 
 namespace {
 
-void OnRemovedPrinter(bool success) {}
+void OnRemovedPrinter(const Printer::PrinterProtocol& protocol, bool success) {
+  if (success) {
+    UMA_HISTOGRAM_ENUMERATION("Printing.CUPS.PrinterRemoved", protocol,
+                              Printer::PrinterProtocol::PROTOCOL_MAX);
+  }
+}
 
 std::unique_ptr<base::DictionaryValue> GetPrinterInfo(const Printer& printer) {
   std::unique_ptr<base::DictionaryValue> printer_info =
@@ -175,12 +181,22 @@ void CupsPrintersHandler::HandleRemoveCupsPrinter(const base::ListValue* args) {
   std::string printer_name;
   CHECK(args->GetString(0, &printer_id));
   CHECK(args->GetString(1, &printer_name));
-  PrintersManagerFactory::GetForBrowserContext(profile_)->RemovePrinter(
-      printer_id);
+  PrintersManager* prefs =
+      PrintersManagerFactory::GetForBrowserContext(profile_);
+  auto printer = prefs->GetPrinter(printer_id);
+
+  if (!printer) {
+    LOG(WARNING) << "Tried to remove non-existant printer";
+    return;
+  }
+  Printer::PrinterProtocol protocol = printer->GetProtocol();
+
+  prefs->RemovePrinter(printer_id);
 
   chromeos::DebugDaemonClient* client =
       chromeos::DBusThreadManager::Get()->GetDebugDaemonClient();
-  client->CupsRemovePrinter(printer_name, base::Bind(&OnRemovedPrinter),
+  client->CupsRemovePrinter(printer_name,
+                            base::Bind(&OnRemovedPrinter, protocol),
                             base::Bind(&base::DoNothing));
 }
 
@@ -257,6 +273,8 @@ void CupsPrintersHandler::OnAddedPrinter(
   std::string printer_name = printer->display_name();
   switch (result_code) {
     case chromeos::PrinterSetupResult::SUCCESS: {
+      UMA_HISTOGRAM_ENUMERATION("Printing.CUPS.PrinterAdded",
+                                printer->GetProtocol(), Printer::PROTOCOL_MAX);
       auto* manager = PrintersManagerFactory::GetForBrowserContext(profile_);
       manager->PrinterInstalled(*printer);
       manager->RegisterPrinter(std::move(printer));