cros sync: Update feature description label in OS settings

* Add real localized text.
* Make text grey via "secondary" text styling.
* Retitle "Turn on" and "Turn off" buttons per latest UX spec.

https://screenshot.googleplex.com/RzQAQfbvwqC

Bug: 1013466
Change-Id: Ibae11cf543479c2038252525282bf6c4511a11f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108098
Commit-Queue: James Cook <jamescook@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751788}

chrome/app/os_settings_strings.grdp

@@ -155,11 +155,14 @@
   <message name="IDS_OS_SETTINGS_SYNC_PAGE_TITLE" desc="Settings sub-page title for sync.">
     Sync your settings
   </message>
-  <message name="IDS_OS_SETTINGS_SYNC_TURN_ON" desc="Button label for turning on sync. Sync is capitalized because it is the proper name of a feature.">
-    Turn on Sync
+  <message name="IDS_OS_SETTINGS_SYNC_TURN_ON" desc="Button label for turning on synchronization of settings across Chrome OS devices.">
+    Turn on
+  </message>
+  <message name="IDS_OS_SETTINGS_SYNC_TURN_OFF" desc="Button label for turning off synchronization of settings across Chrome OS devices.">
+    Turn off
   </message>
-  <message name="IDS_OS_SETTINGS_SYNC_TURN_OFF" desc="Button label for turning off sync. Sync is capitalized because it is the proper name of a feature.">
-    Turn off Sync
+  <message name="IDS_OS_SETTINGS_SYNC_FEATURE_LABEL" desc="Label describing the OS sync feature.">
+    Your apps and settings will sync across all Chrome OS devices where you are signed in with your Google account. For browser sync options, go to<ph name="LINK_BEGIN">&lt;a&gt;</ph>Chrome settings<ph name="LINK_END">&lt;/a&gt;</ph>.
   </message>
   <message name="IDS_OS_SETTINGS_SYNC_APPS_CHECKBOX_LABEL" desc="Label for the checkbox which enables syncing of apps across devices.">
     Apps

chrome/app/os_settings_strings_grdp/IDS_OS_SETTINGS_SYNC_FEATURE_LABEL.png.sha1

+b408bd6da5e3360cd76f954d1ad558549358da4b
\ No newline at end of file

chrome/app/os_settings_strings_grdp/IDS_OS_SETTINGS_SYNC_TURN_OFF.png.sha1

-63f8ef2875ef3f7525c1eb2512c24e64ce2676c2
+b408bd6da5e3360cd76f954d1ad558549358da4b
\ No newline at end of file

chrome/app/os_settings_strings_grdp/IDS_OS_SETTINGS_SYNC_TURN_ON.png.sha1

-e5cee8ca272e5b43525bfdcbf3b465e04e70b2b6
+680fcf18dcf05ea6ce6ae1c9f835d734e7fc1e60
\ No newline at end of file

chrome/browser/resources/settings/chromeos/os_people_page/BUILD.gn

@@ -160,6 +160,7 @@ js_library("os_sync_controls") {
     ":os_sync_browser_proxy",
     "..:metrics_recorder",
     "../../:router",
+    "../localized_link",
     "//ui/webui/resources/cr_elements/cr_toggle:cr_toggle",
     "//ui/webui/resources/js:assert",
     "//ui/webui/resources/js:web_ui_listener_behavior",

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

@@ -7,6 +7,7 @@
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="../../settings_shared_css.html">
+<link rel="import" href="../localized_link/localized_link.html">
 <link rel="import" href="../metrics_recorder.html">
 <link rel="import" href="../os_route.html">
 <link rel="import" href="os_sync_browser_proxy.html">
@@ -86,8 +87,11 @@
       </cr-button>
     </div>
 
-    <div id="featureLabel" class="settings-box" aria-hidden="true">
-      Chrome OS sync feature description PLACEHOLDER
+    <div id="featureLabel" class="settings-box">
+      <settings-localized-link class="secondary"
+          localized-string="$i18n{osSyncFeatureLabel}"
+          link-url="$i18n{browserSettingsSyncSetupUrl}">
+      </settings-localized-link>
     </div>
 
     <div class="settings-box">

chrome/browser/ui/webui/settings/chromeos/os_settings_localized_strings_provider.cc

@@ -10,6 +10,7 @@
 #include "base/feature_list.h"
 #include "base/i18n/number_formatting.h"
 #include "base/no_destructor.h"
+#include "base/strings/strcat.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
@@ -591,8 +592,13 @@ void AddSyncControlsStrings(content::WebUIDataSource* html_source) {
        IDS_SETTINGS_WIFI_CONFIGURATIONS_CHECKBOX_LABEL},
       {"osSyncAppsCheckboxLabel", IDS_OS_SETTINGS_SYNC_APPS_CHECKBOX_LABEL},
       {"osSyncTurnOn", IDS_OS_SETTINGS_SYNC_TURN_ON},
+      {"osSyncFeatureLabel", IDS_OS_SETTINGS_SYNC_FEATURE_LABEL},
   };
   AddLocalizedStringsBulk(html_source, kLocalizedStrings);
+
+  html_source->AddString(
+      "browserSettingsSyncSetupUrl",
+      base::StrCat({chrome::kChromeUISettingsURL, chrome::kSyncSetupSubPage}));
 }
 
 void AddCrostiniStrings(content::WebUIDataSource* html_source,