Settings: fix search's associated control for edit profile subpage

A bug occured when searching through settings page, because one of
the controls associated with the "edit person" subpage does not exist
if DICE is enabled. This CL points it to a different control when DICE
is enabled.

Bug: 876280
Change-Id: I24049100f2b2357ada85b07a44c893a39fd1b66b
Reviewed-on: https://chromium-review.googlesource.com/1198006
Commit-Queue: Scott Chen <scottchen@chromium.org>
Reviewed-by: Esmael El-Moslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587862}

chrome/browser/resources/settings/people_page/people_page.html

@@ -450,7 +450,7 @@
 <if expr="not chromeos">
       <template is="dom-if" route-path="/manageProfile">
         <settings-subpage
-            associated-control="[[$$('#picture-subpage-trigger')]]"
+            associated-control="[[getEditPersonAssocControl_(diceEnabled_)]]"
             page-title="$i18n{editPerson}">
           <settings-manage-profile profile-name="[[profileName_]]"
               sync-status="[[syncStatus]]">

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

@@ -262,6 +262,15 @@ Polymer({
     }
   },
 
+  /**
+   * @return {!Element}
+   * @private
+   */
+  getEditPersonAssocControl_: function() {
+    return this.diceEnabled_ ? assert(this.$$('#edit-profile')) :
+                               assert(this.$$('#picture-subpage-trigger'));
+  },
+
   // <if expr="chromeos">
   /** @private */
   getPasswordState_: function(hasPin, enableScreenLock) {