Add a policy_browsertest for the DefaultWebBluetoothGuardSetting.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 269aaeea4fde940d6224f57b611ef89920ec743f..44666715604e2b42fdb6f3ea10046eceeb54f479 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -222,6 +222,10 @@ bool ContentBrowserClient::AllowKeygen(const GURL& url,
   return true;
 }
 
+bool ContentBrowserClient::AllowWebBluetooth() {
+  return true;
+}
+
 QuotaPermissionContext* ContentBrowserClient::CreateQuotaPermissionContext() {
   return nullptr;
 }