Fix Loading text for settings-dropdown-menu

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

Index: chrome/test/data/webui/settings/dropdown_menu_tests.js
diff --git a/chrome/test/data/webui/settings/dropdown_menu_tests.js b/chrome/test/data/webui/settings/dropdown_menu_tests.js
index 77c3768ded422a0a4a0752bf58fe4f5f3ec5307a..1bb7576e4e9a975a7e840a540fe5b396751fc0c3 100644
--- a/chrome/test/data/webui/settings/dropdown_menu_tests.js
+++ b/chrome/test/data/webui/settings/dropdown_menu_tests.js
@@ -92,6 +92,32 @@ cr.define('settings_dropdown_menu', function() {
         // Pref should not have changed.
         assertEquals('f', dropdown.pref.value);
       });
+
+      test('delay setting options', function testDelayedOptions(done) {
+        dropdown.pref = {
+          key: 'test.number2',
+          type: chrome.settingsPrivate.PrefType.NUMBER,
+          value: 200,
+        };
+
+        setTimeout(function() {

[dschuyler, 2016/08/11 23:50:58]

What other choices do we have aside from using
a setTimeout here? Can the setTimeout be replaced
with something event based? (i.e. some active 
confirmation that it's ready rather than a passive
time delay).

[michaelpg, 2016/08/16 23:38:11]

In this case the point of the test is to spin for a while and test that setting
the dropdown menu options, after a time, still works. Not to run a test
immediately when it's ready -- it's "not ready" here because there are no
options.

providing a time like 100 ensures that any other work that might be scheduled
runs first, which is what we want. (theoretically async tasks could take longer
than 100 ms, then schedule more async tasks, but I think the test suffices as
written.)

[dschuyler, 2016/08/17 23:59:46]

Ah, I think I was hoping for a different kind of test.
One that would test that the user sees the message 
about "Loading..." while we are waiting for the data.

[michaelpg, 2016/08/19 00:41:23]

Yes, that's what this tests: without setting menuOptions, after 100ms the label
is 'loading' and nothing is selected (so the label is shown).

I was just talking about why the 100ms timeout makes sense to do that.

+          assertEquals(
+              loadTimeData.getValue('loading'), dropdown.$.dropdownMenu.label);
+          assertTrue(dropdown.$.dropdownMenu.disabled);
+          assertEquals(undefined, selectable.selected);
+
+          dropdown.menuOptions = [{value: 100, name: 'Option 100'},
+                                  {value: 200, name: 'Option 200'},
+                                  {value: 300, name: 'Option 300'},
+                                  {value: 400, name: 'Option 400'}];
+          Polymer.dom.flush();
+
+          // Dropdown menu enables itself.
+          assertFalse(dropdown.$.dropdownMenu.disabled);
+          assertEquals(200, dropdown.pref.value);

[dschuyler, 2016/08/11 23:50:58]

Consider making a comment in the code about
what this assert is implying / why it's part of this
test.

[michaelpg, 2016/08/16 23:38:10]

Done, also this probably wasn't the right thing to test!

+          done();
+        }, 100);
+      });
     });
   }