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..ed8935a0f6c6b4a582189a454268899651ea3308 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);
-
-        MockInteractions.tap(
-            spellCheckCollapse.querySelector('.list-button:last-of-type'));
-        assertTrue(!!languagesPage.$$('settings-edit-dictionary-page'));
       }
     });
+
+    if (!cr.isMac) {
+      test('spellcheck edit dictionary page add word button', function() {

[dpapad, 2017/02/07 00:47:16]

Nit (optional): s/add word button/add word validation/

[scottchen, 2017/02/08 00:43:19]

Addressed in new CL: https://codereview.chromium.org/2682893002

+        assertFalse(!!languagesPage.$$('settings-edit-dictionary-page'));
+        var spellCheckCollapse = languagesPage.$.spellCheckCollapse;
+        MockInteractions.tap(
+            spellCheckCollapse.querySelector('.list-button'));
+        var editDictPage = languagesPage.$$('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.