MD Settings: hide signin-related UI when signin is disabled (e.g. by policy)

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 6858d898e90a728d3df4a76b67636e70dd522b2e..339bb56e443d220b66dd27325ef3977f9bc57624 100644
--- a/chrome/browser/resources/settings/people_page/people_page.js
+++ b/chrome/browser/resources/settings/people_page/people_page.js
@@ -358,4 +358,12 @@ Polymer({
   getIconImageset_: function(iconUrl) {
     return cr.icon.getImage(iconUrl);
   },
+
+  /**
+   * @return {boolean} Whether to show the "Sign in to Chrome" button.
+   * @private
+   */
+  showSignin_: function(syncStatus) {
+    return syncStatus.signinAllowed && !syncStatus.signedIn;
+  },
 });