[CUPS] Implement the Webui handler for the printers auto discovery.

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

Index: chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.h
diff --git a/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.h b/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.h
index 3153c15b0cedcbf06ddef21ca5e529488f1dced3..8c30a2ed0996f5a4efff3753dd3f6e02cef99b36 100644
--- a/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.h
+++ b/chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.h
@@ -8,6 +8,7 @@
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
 #include "chromeos/printing/printer_configuration.h"
+#include "chromeos/printing/printer_discoverer.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
 
 namespace base {
@@ -21,22 +22,22 @@ namespace settings {
 
 // Chrome OS CUPS printing settings page UI handler.
 class CupsPrintersHandler : public ::settings::SettingsPageUIHandler,
-                            public ui::SelectFileDialog::Listener {
+                            public ui::SelectFileDialog::Listener,
+                            public chromeos::PrinterDiscoverer::Observer {
  public:
   explicit CupsPrintersHandler(content::WebUI* webui);
   ~CupsPrintersHandler() override;
 
   // SettingsPageUIHandler overrides:
   void RegisterMessages() override;
-  void OnJavascriptAllowed() override{};
-  void OnJavascriptDisallowed() override{};
+  void OnJavascriptAllowed() override {}
+  void OnJavascriptDisallowed() override {}
 
  private:
   // Gets all CUPS printers and return it to WebUI.
   void HandleGetCupsPrintersList(const base::ListValue* args);
   void HandleUpdateCupsPrinter(const base::ListValue* args);
   void HandleRemoveCupsPrinter(const base::ListValue* args);
-  void OnRemovedPrinter(const std::string& printer_id, bool success);
 
   void HandleAddCupsPrinter(const base::ListValue* args);
   void OnAddedPrinter(std::unique_ptr<Printer> printer, bool success);
@@ -49,6 +50,15 @@ class CupsPrintersHandler : public ::settings::SettingsPageUIHandler,
                     int index,
                     void* params) override;
 
+  void HandleStartDiscovery(const base::ListValue* args);
+  void HandleStopDiscovery(const base::ListValue* args);
+
+  // chromeos::PrinterDiscoverer::Observer override:
+  void OnPrintersFound(const std::vector<Printer>& printers) override;
+  void OnDiscoveryDone() override;
+
+  std::unique_ptr<chromeos::PrinterDiscoverer> printer_discoverer_;
+
   Profile* profile_;
   scoped_refptr<ui::SelectFileDialog> select_file_dialog_;
   std::string webui_callback_id_;