Add a new app API to enable watchdog behavior restarts in kiosk apps

extensions/browser/test_runtime_api_delegate.cc

Index: extensions/browser/test_runtime_api_delegate.cc
diff --git a/extensions/browser/test_runtime_api_delegate.cc b/extensions/browser/test_runtime_api_delegate.cc
index d9624b5839d79cb94fb6296177b013b58527694b..d71abc2f98670be8a2d10d116352f719d2e6f423 100644
--- a/extensions/browser/test_runtime_api_delegate.cc
+++ b/extensions/browser/test_runtime_api_delegate.cc
@@ -50,4 +50,7 @@ bool TestRuntimeAPIDelegate::RestartDevice(std::string* error_message) {
   return false;
 }
 
+void TestRuntimeAPIDelegate::SetOnDeviceShutdownCallback(
+    const base::Closure& callback) {}
+
 }  // namespace extensions