[CUPS] If no printers is auto-discovered, show the manual printer setup dialog

chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js

Index: chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js
diff --git a/chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js b/chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js
index 0fee051cf95d01558a8fc13a7ede461664bfefbe..aea91eb0e4261c88cd6c248284696f6f0856a883 100644
--- a/chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js
+++ b/chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.js
@@ -84,8 +84,10 @@ Polymer({
         'on-printer-discovered', this.onPrinterDiscovered_.bind(this));
     this.addWebUIListener(
         'on-printer-discovery-done', this.onPrinterDiscoveryDone_.bind(this));
-    this.addWebUIListener(
-        'on-printer-discovery-failed', this.onPrinterDiscoveryDone_.bind(this));
+  },
+
+  close: function() {
+    this.$$('add-printer-dialog').close();
   },
 
   /**
@@ -106,7 +108,10 @@ Polymer({
   onPrinterDiscoveryDone_: function() {
     this.discovering_ = false;
     this.$$('add-printer-list').style.maxHeight = kPrinterListFullHeight + 'px';
-    this.$.noPrinterMessage.hidden = !!this.discoveredPrinters;
+    this.$.noPrinterMessage.hidden = !!this.discoveredPrinters.length;
+
+    if (!this.discoveredPrinters.length)
+      this.fire('no-detected-printer');
   },
 
   /** @private */
@@ -378,6 +383,7 @@ Polymer({
     'open-configuring-printer-dialog': 'openConfiguringPrinterDialog_',
     'open-discovery-printers-dialog': 'openDiscoveryPrintersDialog_',
     'open-manufacturer-model-dialog': 'openManufacturerModelDialog_',
+    'no-detected-printer': 'onNoDetectedPrinter_',
   },
 
   /** @override */
@@ -510,6 +516,17 @@ Polymer({
     }
   },
 
+  /** @private */
+  onNoDetectedPrinter_: function() {
+    // If there is no detected printer, automatically open manually-add-printer
+    // dialog only when the user opens the discovery-dialog through the
+    // "ADD PRINTER" button.
+    if (!this.previousDialog_) {
+      this.$$('add-printer-discovery-dialog').close();
+      this.openManuallyAddPrinterDialog_();
+    }
+  },
+
   /**
    * Switch dialog from |fromDialog| to |toDialog|.
    * @param {string} fromDialog