md-settings: wrap lock screen dialogs in dom-if.

chrome/browser/resources/settings/people_page/fingerprint_list.js

Index: chrome/browser/resources/settings/people_page/fingerprint_list.js
diff --git a/chrome/browser/resources/settings/people_page/fingerprint_list.js b/chrome/browser/resources/settings/people_page/fingerprint_list.js
index 442c53cc2187584284fe732e2a87b0770160d047..474bb6c080eff7469c4b7355f8a5e67b23ef2888 100644
--- a/chrome/browser/resources/settings/people_page/fingerprint_list.js
+++ b/chrome/browser/resources/settings/people_page/fingerprint_list.js
@@ -31,7 +31,10 @@ Polymer({
       value: function() {
         return [];
       }
-    }
+    },
+
+    /** @private */
+    showSetupFingerprintDialog_: Boolean,
   },
 
   /** @private {?settings.FingerprintBrowserProxy} */
@@ -145,11 +148,12 @@ Polymer({
    * @private
    */
   openAddFingerprintDialog_: function() {
-    this.$.setupFingerprint.open();
+    this.showSetupFingerprintDialog_ = true;
   },
 
   /** @private */
   onSetupFingerprintDialogClose_: function() {
+    this.showSetupFingerprintDialog_ = false;
     cr.ui.focusWithoutInk(assert(this.$$('#addFingerprint')));
     this.browserProxy_.startAuthentication();
   },
@@ -162,7 +166,7 @@ Polymer({
   onScreenLocked_: function(screenIsLocked) {
     if (!screenIsLocked &&
         settings.getCurrentRoute() == settings.Route.FINGERPRINT) {
-      this.$.setupFingerprint.close();
+      this.onSetupFingerprintDialogClose_();
     }
   },
 });