Make some secure DNS setting tests interactive to fix flakiness.

Most tests involving the dropdown or custom input field have been moved
to the new secure_dns_interactive_test.js as they involve testing for
focus.

This cl also re-enables CrSettingsSecureDnsTest.All, which was disabled
when the flakiness was observed.

Bug: 1040145,1057504
Change-Id: I7813849295ddf6a3ddc283a9cdd9416db64b8f2b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2083760Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: Katharine Daly <dalyk@google.com>
Cr-Commit-Position: refs/heads/master@{#746591}

chrome/browser/resources/settings/privacy_page/secure_dns_input.html

@@ -22,7 +22,7 @@
     <cr-input id="input" value="{{value}}"
         placeholder="$i18n{secureDnsCustomPlaceholder}" invalid="[[showError_]]"
         error-message="[[errorText_]]" maxlength="102400" spellcheck="false"
-        on-input="onInput_" on-blur="onBlur_">
+        on-input="onInput_" on-blur="validate">
     </cr-input>
   </template>
   <script src="secure_dns_input.js"></script>

chrome/browser/resources/settings/privacy_page/secure_dns_input.js

@@ -51,9 +51,8 @@ Polymer({
    * When the custom input field loses focus, validate the current value and
    * trigger an event with the result. Show an error message if the validated
    * value is still the most recent value, is invalid, and is non-empty.
-   * @private
    */
-  onBlur_: function() {
+  validate: function() {
     const valueToValidate = this.value;
     this.browserProxy_.validateCustomDnsEntry(valueToValidate).then(valid => {
       this.showError_ =

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

@@ -1025,8 +1025,7 @@ CrSettingsSecureDnsTest.prototype = {
   ]),
 };
 
-// Disabled due to flakiness: https://crbug.com/1057504.
-TEST_F('CrSettingsSecureDnsTest', 'DISABLED_All', function() {
+TEST_F('CrSettingsSecureDnsTest', 'All', function() {
   mocha.run();
 });
 

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

@@ -72,3 +72,29 @@ CrSettingsAnimatedPagesTest.prototype = {
 TEST_F('CrSettingsAnimatedPagesTest', 'All', function() {
   mocha.run();
 });
+
+
+/**
+ * @constructor
+ * @extends {CrSettingsBrowserTest}
+ */
+function CrSettingsSecureDnsTest() {}
+
+CrSettingsSecureDnsTest.prototype = {
+  __proto__: CrSettingsInteractiveUITest.prototype,
+
+  /** @override */
+  browsePreload: 'chrome://settings/privacy_page/secure_dns.html',
+
+  /** @override */
+  extraLibraries: CrSettingsInteractiveUITest.prototype.extraLibraries.concat([
+    '../test_util.js',
+    '../test_browser_proxy.js',
+    'test_privacy_page_browser_proxy.js',
+    'secure_dns_interactive_test.js',
+  ]),
+};
+
+TEST_F('CrSettingsSecureDnsTest', 'All', function() {
+  mocha.run();
+});