Remove openglui embedder code

runtime/embedders/openglui/common/lifecycle_handler.h

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#ifndef EMBEDDERS_OPENGLUI_COMMON_LIFECYCLE_HANDLER_H_
-#define EMBEDDERS_OPENGLUI_COMMON_LIFECYCLE_HANDLER_H_
-
-class LifeCycleHandler {
-  public:
-    virtual int32_t OnStart() = 0;
-    virtual int32_t Activate() = 0;
-    virtual void Deactivate() = 0;
-    virtual int32_t OnStep() = 0;
-    virtual void Pause() {}
-    virtual int32_t Resume() {
-      return 0;
-    }
-    virtual void FreeAllResources() {}
-    virtual void OnSaveState(void** data, size_t* size) {}
-    virtual void OnConfigurationChanged() {}
-    virtual void OnLowMemory() {}
-    virtual ~LifeCycleHandler() {}
-};
-
-#endif  // EMBEDDERS_OPENGLUI_COMMON_LIFECYCLE_HANDLER_H_
-