Fix Undo Toast Behavior

This change fixes the undo toast so that navigating away from the
password settings page will hide it if shown.

Bug: 779945
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I0e10f352701c7caf356e070f2b4c6f7cd8b59b41
Reviewed-on: https://chromium-review.googlesource.com/779200Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519438}

chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.js

@@ -356,6 +356,9 @@ Polymer({
     this.passwordManager_.removeExceptionListChangedListener(
         /** @type {function(!Array<PasswordManager.ExceptionEntry>):void} */ (
             this.setPasswordExceptionsListener_));
+
+    if (this.$.undoToast.open)
+      this.$.undoToast.hide();
   },
 
   /**

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

@@ -572,6 +572,26 @@ TEST_F('SettingsPasswordSectionBrowserTest', 'uiTests', function() {
 
       MockInteractions.tap(exportDialog.$.exportPasswordsButton);
     });
+
+    test('closingPasswordsSectionHidesUndoToast', function(done) {
+      var passwordEntry = FakeDataMaker.passwordEntry('goo.gl', 'bart', 1);
+      var passwordsSection =
+          createPasswordsSection(passwordManager, [passwordEntry], []);
+
+      // Click the remove button on the first password and assert that an undo
+      // toast is shown.
+      var firstNode = Polymer.dom(passwordsSection.$.passwordList).children[1];
+      MockInteractions.tap(firstNode.$$('#passwordMenu'));
+      MockInteractions.tap(passwordsSection.$.menuRemovePassword);
+      assertTrue(passwordsSection.$.undoToast.open);
+
+      // Remove the passwords section from the DOM and check that this closes
+      // the undo toast.
+      document.body.removeChild(passwordsSection);
+      assertFalse(passwordsSection.$.undoToast.open);
+
+      done();
+    });
   });
 
   mocha.run();