Speed up ARC boot if the user launches ARC app while ARC is not ready

chrome/browser/chromeos/settings/device_settings_test_helper.cc

Index: chrome/browser/chromeos/settings/device_settings_test_helper.cc
diff --git a/chrome/browser/chromeos/settings/device_settings_test_helper.cc b/chrome/browser/chromeos/settings/device_settings_test_helper.cc
index 69b0978d5f93d6afbba9ec4a2bf3fef18b94f522..0c13cb7f84b36f929bef85f186152f23b744f7ac 100644
--- a/chrome/browser/chromeos/settings/device_settings_test_helper.cc
+++ b/chrome/browser/chromeos/settings/device_settings_test_helper.cc
@@ -189,6 +189,9 @@ void DeviceSettingsTestHelper::StartArcInstance(
 
 void DeviceSettingsTestHelper::StopArcInstance(const ArcCallback& callback) {}
 
+void DeviceSettingsTestHelper::PrioritizeArcInstance(
+    const ArcCallback& callback) {}
+
 void DeviceSettingsTestHelper::GetArcStartTime(
     const GetArcStartTimeCallback& callback) {}