Refactor PrinterDiscoverer and PrinterDetector to use a common interface.

chrome/browser/chromeos/BUILD.gn

Index: chrome/browser/chromeos/BUILD.gn
diff --git a/chrome/browser/chromeos/BUILD.gn b/chrome/browser/chromeos/BUILD.gn
index f052a5036105bd24dbdf96e5200d125bb1f58c25..c4c84a32eca134c27ad7053ef9d548e14f28bb65 100644
--- a/chrome/browser/chromeos/BUILD.gn
+++ b/chrome/browser/chromeos/BUILD.gn
@@ -1308,6 +1308,8 @@ source_set("chromeos") {
     "power/renderer_freezer.h",
     "preferences.cc",
     "preferences.h",
+    "printing/combining_printer_detector.cc",
+    "printing/combining_printer_detector.h",
     "printing/cups_print_job.cc",
     "printing/cups_print_job.h",
     "printing/cups_print_job_manager.cc",
@@ -1322,8 +1324,7 @@ source_set("chromeos") {
     "printing/ppd_provider_factory.h",
     "printing/printer_configurer.cc",
     "printing/printer_configurer.h",
-    "printing/printer_discoverer.cc",
-    "printing/printer_discoverer.h",
+    "printing/printer_detector.h",
     "printing/printer_info.h",
     "printing/printers_manager.cc",
     "printing/printers_manager.h",
@@ -1842,6 +1843,7 @@ source_set("unit_tests") {
     "power/power_prefs_unittest.cc",
     "power/renderer_freezer_unittest.cc",
     "preferences_unittest.cc",
+    "printing/combining_printer_detector_unittest.cc",
     "printing/printers_manager_unittest.cc",
     "printing/specifics_translation_unittest.cc",
     "profiles/profile_list_chromeos_unittest.cc",