Show message when no nearby printers available

When there are no nearby printers available, show a message indicating
that.

Bug: 991929
Change-Id: If430ff4c526120aa0b0c97f1670b6e68d6a0f1d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1754942Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#687316}

chrome/app/settings_strings.grdp

@@ -1583,8 +1583,8 @@
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_UNAVAILABLE_MESSAGE" desc="The message shown when a printer can no longer be contacted while being added.">
       <ph name="PRINTER_NAME">$1<ex>Acme Printer</ex></ph> is no longer available
     </message>
-    <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_NO_PRINTER_NEARBY" desc="The no-printer-found message shown in the auto discovery dialog.">
-      No printers nearby
+    <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_NO_PRINTER_NEARBY" desc="The message shown when no nearby printers are found.">
+      There are no available printers.
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_SEARCHING_NEARBY_PRINTER" desc="The searching-in-progress message shown in the auto discovery dialog.">
       Searching...

chrome/browser/resources/settings/printing_page/cups_nearby_printers.html

@@ -8,10 +8,19 @@
 
 <dom-module id="settings-cups-nearby-printers">
   <template>
-    <style include="settings-shared"></style>
+    <style include="settings-shared">
+      #noPrinterMessage {
+        margin-inline-start: 60px;
+        margin-top: 20px;
+      }
+    </style>
     <settings-cups-printers-entry-list printers="[[nearbyPrinters_]]"
         search-term="[[searchTerm]]">
     </settings-cups-printers-entry-list>
+    <div class="secondary" id="noPrinterMessage"
+        hidden="[[nearbyPrinters_.length]]">
+        $i18n{noPrinterNearbyMessage}
+    </div>
   </template>
   <script src="cups_nearby_printers.js"></script>
 </dom-module>

chrome/test/data/webui/settings/chromeos/cups_printer_landing_page_tests.js

@@ -669,4 +669,31 @@ suite('CupsNearbyPrintersTests', function() {
           verifyPrintersList(nearbyPrinterEntries, expectedPrinterList);
         });
   });
+
+  test('No Nearby Printers', function() {
+    const automaticPrinterList = [];
+    const discoveredPrinterList = [createCupsPrinterInfo('test3', '3', 'id3')];
+
+    return test_util.flushTasks().then(() => {
+      nearbyPrintersElement = page.$$('settings-cups-nearby-printers');
+      assertTrue(!!nearbyPrintersElement);
+
+      // Assert that there are no nearby printers.
+      let nearbyPrinterEntries = getPrinterEntries(nearbyPrintersElement);
+      assertEquals(0, nearbyPrinterEntries.length);
+
+      // Check that the "No available printers" message is shown.
+      assertFalse(nearbyPrintersElement.$$('#noPrinterMessage').hidden);
+
+      // Simuluate finding nearby printers.
+      cr.webUIListenerCallback(
+          'on-nearby-printers-changed', automaticPrinterList,
+          discoveredPrinterList);
+
+      Polymer.dom.flush();
+
+      // Check that the "No available printers" message is not shown.
+      assertTrue(nearbyPrintersElement.$$('#noPrinterMessage').hidden);
+    });
+  });
 });