MD Settings: Use dom-if for the profile disconnect dialog.

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

Index: chrome/browser/resources/settings/people_page/people_page.js
diff --git a/chrome/browser/resources/settings/people_page/people_page.js b/chrome/browser/resources/settings/people_page/people_page.js
index da7961a3529deb418d5bf444cc81cf6f6818861d..568e9a0f94636603de2f83bc54b7e52964881bb9 100644
--- a/chrome/browser/resources/settings/people_page/people_page.js
+++ b/chrome/browser/resources/settings/people_page/people_page.js
@@ -53,6 +53,9 @@ Polymer({
       value: function() {
         return settings.SyncBrowserProxyImpl.getInstance();
       },
+
+      /** @private */
+      showingDisconnectDialog_: Boolean,
     },
 
 <if expr="chromeos">
@@ -217,21 +220,29 @@ Polymer({
 
   /** @private */
   onDisconnectTap_: function() {
-    this.$.disconnectDialog.showModal();
+    this.showingDisconnectDialog_ = true;
+    this.async(function() {
+      this.$$('#disconnectDialog').showModal();
+    }.bind(this));
   },
 
   /** @private */
   onDisconnectCancel_: function() {
-    this.$.disconnectDialog.close();
+    this.$$('#disconnectDialog').close();
   },
 
   /** @private */
   onDisconnectConfirm_: function() {
     var deleteProfile = !!this.syncStatus.domain ||
-        (this.$.deleteProfile && this.$.deleteProfile.checked);
+        (this.$$('#deleteProfile') && this.$$('#deleteProfile').checked);
     this.syncBrowserProxy_.signOut(deleteProfile);
 
-    this.$.disconnectDialog.close();
+    this.$$('#disconnectDialog').close();
+  },
+
+  /** @private */
+  onDisconnectDialogClosed_: function() {
+    this.showingDisconnectDialog_ = false;
   },
 
   /** @private */