NOT FOR REVIEW - convert to cc animation

chrome/browser/android/vr_shell/ui_elements/exit_prompt_backplane.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/vr_shell/ui_elements/exit_prompt_backplane.h"
 
 #include "base/memory/ptr_util.h"
 
 namespace vr_shell {
 
 ExitPromptBackplane::ExitPromptBackplane(
+    int id,
     const base::Callback<void()>& click_callback)
-    : click_callback_(click_callback) {}
+    : UiElement(id), click_callback_(click_callback) {}
 
 ExitPromptBackplane::~ExitPromptBackplane() = default;
 
 void ExitPromptBackplane::OnButtonUp(const gfx::PointF& position) {
   // We always run the callback. That is, if the user clicks the controller
   // button on the backplane and releases it on another element in front of the
   // backplane, this callback will still be called. Elements are input locked
   // on button down and it's probably not worth special-casing the backplane.
   click_callback_.Run();
 }
 
 }  // namespace vr_shell