MD Settings: in spell-check page, disable add button when input is empty.

chrome/test/data/webui/settings/languages_page_browsertest.js

Index: chrome/test/data/webui/settings/languages_page_browsertest.js
diff --git a/chrome/test/data/webui/settings/languages_page_browsertest.js b/chrome/test/data/webui/settings/languages_page_browsertest.js
index abed7bc973ff1efcbfdbd1cca19a175059065656..e52a28094202331227182bc4e8d20322a16646db 100644
--- a/chrome/test/data/webui/settings/languages_page_browsertest.js
+++ b/chrome/test/data/webui/settings/languages_page_browsertest.js
@@ -447,12 +447,25 @@ TEST_F('SettingsLanguagesPageBrowserTest', 'MAYBE_LanguagesPage', function() {
         assertTrue(triggerRow.classList.contains('two-line'));
         assertLT(
             0, triggerRow.querySelector('.secondary').textContent.length);
+      }
+    });
 
+    if (!cr.isMac) {
+      test('spellcheck edit dictionary page add word button', function() {
+        assertFalse(!!languagesPage.$$('settings-edit-dictionary-page'));
+        var spellCheckCollapse = languagesPage.$.spellCheckCollapse;
         MockInteractions.tap(
             spellCheckCollapse.querySelector('.list-button:last-of-type'));

[dpapad, 2017/02/06 22:40:59]

Are you sure that this selector works as expected? AFAIK first-of-type,
last-of-type can only used with element tags, not CSS clases, for example

div:last-of-type OK
p: first-of-type OK
.foo:last-of-type NOT OK

[scottchen, 2017/02/06 23:38:31]

The (non-)existence of the subpage is checked before and after the target
element is mock-tapped, so I think it's selecting the collapse button as
intended.
Also, :last-of-type seems to work with class. See:
https://jsfiddle.net/dLwyqwwh/

-        assertTrue(!!languagesPage.$$('settings-edit-dictionary-page'));
-      }
-    });
+        var editDictPage = languagesPage.$$('settings-edit-dictionary-page');
+        assertTrue(!!editDictPage);
+        var addWordButton = editDictPage.root.querySelector('paper-button');
+        editDictPage.$.newWord.value = '';
+        assertTrue(!!addWordButton);
+        assertTrue(addWordButton.disabled);
+        editDictPage.$.newWord.value = 'valid word';
+        assertFalse(addWordButton.disabled);
+      });
+    }
   }.bind(this));
 
   // TODO(michaelpg): Test more aspects of the languages UI.