Make CUPS USB printing play better with the settings page. This change does several things:

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 59c39b4516c43bc5f6175f45bbb274e765662426..bad955b60859a4c7a509a9b43397891f48be43e9 100644
--- a/chrome/browser/chromeos/BUILD.gn
+++ b/chrome/browser/chromeos/BUILD.gn
@@ -1227,12 +1227,11 @@ source_set("chromeos") {
     "printing/cups_print_job_notification.h",
     "printing/cups_print_job_notification_manager.cc",
     "printing/cups_print_job_notification_manager.h",
-    "printing/fake_printer_discoverer.cc",
-    "printing/fake_printer_discoverer.h",

[skau, 2017/03/31 17:50:11]

I know I told you to keep these, but can you delete them?  We can always
resurrect them from the git history. If they're not compiled, they'll just get
out of date anyway.

[Carlson, 2017/03/31 18:20:06]

Done.

     "printing/ppd_provider_factory.cc",
     "printing/ppd_provider_factory.h",
     "printing/printer_configurer.cc",
     "printing/printer_configurer.h",
+    "printing/printer_discoverer.cc",
     "printing/printer_discoverer.h",
     "printing/printers_manager.cc",
     "printing/printers_manager.h",