chromeos: Fix DCHECK when searching OS settings for not-found string

The C++ OSSyncHandler is only instantiated when the SplitSettingsSync
flag is set. However, the new os-sync-controls HTML/JS can be
instantiated by a search event when the flag is not set. This leads
to a DCHECK for an unhandled message.

Only instantiate the HTML if the flag is set. Do the same for the
old UI.

Fixed: 1044369
Change-Id: If09060e9916405afc524e669f235166cedf8c4eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017986Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734718}

chrome/browser/resources/settings/chromeos/os_people_page/os_people_page.html

@@ -172,23 +172,27 @@
       </template>
 
       <!-- Pre-SplitSettingsSync we show the browser's sync controls. -->
-      <template is="dom-if" route-path="/syncSetup/advanced">
-        <settings-subpage page-title="$i18n{syncAdvancedPageTitle}"
-            associated-control="[[$$('#sync-setup')]]"
-            learn-more-url="$i18n{syncAndGoogleServicesLearnMoreURL}">
-          <settings-sync-controls sync-status="[[syncStatus]]">
-          </settings-sync-controls>
-        </settings-subpage>
+      <template is="dom-if" if="[[!splitSettingsSyncEnabled_]]">
+        <template is="dom-if" route-path="/syncSetup/advanced">
+          <settings-subpage page-title="$i18n{syncAdvancedPageTitle}"
+              associated-control="[[$$('#sync-setup')]]"
+              learn-more-url="$i18n{syncAndGoogleServicesLearnMoreURL}">
+            <settings-sync-controls sync-status="[[syncStatus]]">
+            </settings-sync-controls>
+          </settings-subpage>
+        </template>
       </template>
 
       <!-- Post-SplitSettingsSync we have separate OS sync controls. -->
-      <template is="dom-if" route-path="/osSync">
-        <settings-subpage page-title="$i18n{osSyncPageTitle}"
-            associated-control="[[$$('#sync-setup')]]"
-            learn-more-url="$i18n{syncAndGoogleServicesLearnMoreURL}">
-          <os-sync-controls sync-status="[[syncStatus]]">
-          </os-sync-controls>
-        </settings-subpage>
+      <template is="dom-if" if="[[splitSettingsSyncEnabled_]]">
+        <template is="dom-if" route-path="/osSync">
+          <settings-subpage page-title="$i18n{osSyncPageTitle}"
+              associated-control="[[$$('#sync-setup')]]"
+              learn-more-url="$i18n{syncAndGoogleServicesLearnMoreURL}">
+            <os-sync-controls sync-status="[[syncStatus]]">
+            </os-sync-controls>
+          </settings-subpage>
+        </template>
       </template>
 
       <template is="dom-if" route-path="/lockScreen">

chrome/browser/resources/settings/chromeos/os_route.js

@@ -22,7 +22,9 @@ cr.define('settings', function() {
     if (!loadTimeData.getBoolean('isGuest')) {
       r.PEOPLE = r.BASIC.createSection('/people', 'people');
       r.SYNC = r.PEOPLE.createChild('/syncSetup');
-      r.SYNC_ADVANCED = r.SYNC.createChild('/syncSetup/advanced');
+      if (!loadTimeData.getBoolean('splitSettingsSyncEnabled')) {
+        r.SYNC_ADVANCED = r.SYNC.createChild('/syncSetup/advanced');
+      }
     }
 
     r.INTERNET = r.BASIC.createSection('/internet', 'internet');
@@ -102,8 +104,7 @@ cr.define('settings', function() {
     r.ACCESSIBILITY = r.ADVANCED.createSection('/accessibility', 'a11y');
 
     if (!loadTimeData.getBoolean('isGuest')) {
-      if (loadTimeData.valueExists('splitSettingsSyncEnabled') &&
-          loadTimeData.getBoolean('splitSettingsSyncEnabled')) {
+      if (loadTimeData.getBoolean('splitSettingsSyncEnabled')) {
         r.OS_SYNC = r.PEOPLE.createChild('/osSync');
       }
       // Personalization