Propagate Chrome OS language to the Add Supervision flow.

Bug: 927957
Change-Id: I87dbdbb240f41bd8e3ba90959db5dd802ee34e62
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715305
Commit-Queue: Felipe Cerqueira <cerqueira@google.com>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680420}

chrome/browser/resources/chromeos/add_supervision/add_supervision.js

@@ -79,11 +79,13 @@ Polymer({
       const accessToken = result.oauthToken;
       const flowType = loadTimeData.getString('flowType');
       const platformVersion = loadTimeData.getString('platformVersion');
+      const languageCode = loadTimeData.getString('languageCode');
 
       const url = new URL(webviewUrl);
       url.searchParams.set('flow_type', flowType);
       url.searchParams.set('platform_version', platformVersion);
       url.searchParams.set('access_token', accessToken);
+      url.searchParams.set('hl', languageCode);
 
       // Allow guest webview content to open links in new windows.
       webview.addEventListener('newwindow', function(e) {

chrome/browser/ui/webui/chromeos/add_supervision/add_supervision_ui.cc

@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "base/no_destructor.h"
 #include "base/system/sys_info.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/supervised_user/supervised_user_service.h"
@@ -19,6 +20,7 @@
 #include "chrome/common/webui_url_constants.h"
 #include "chrome/grit/browser_resources.h"
 #include "chrome/grit/generated_resources.h"
+#include "components/google/core/common/google_util.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "mojo/public/cpp/bindings/binding.h"
@@ -172,6 +174,11 @@ void AddSupervisionUI::SetupResources() {
   source->AddString("platformVersion", base::SysInfo::OperatingSystemVersion());
   source->AddString("flowType", kAddSupervisionFlowType);
 
+  // Forward the browser language code.
+  source->AddString(
+      "languageCode",
+      google_util::GetGoogleLocale(g_browser_process->GetApplicationLocale()));
+
   content::WebUIDataSource::Add(profile, source.release());
 }