Remove openglui embedder code

runtime/embedders/openglui/common/resource.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_RESOURCE_H_
-#define EMBEDDERS_OPENGLUI_COMMON_RESOURCE_H_
-
-#include <stdlib.h>
-#include <string.h>
-
-class Resource {
-  public:
-    explicit Resource(const char* path)
-        :  descriptor_(-1),
-           start_(0),
-           length_(-1) {
-      path_ = strdup(path);
-    }
-
-    const char* path() {
-      return path_;
-    }
-
-    virtual int32_t descriptor() {
-      return descriptor_;
-    }
-
-    virtual off_t start() {
-      return start_;
-    }
-
-    virtual off_t length() {
-      return length_;
-    }
-
-    virtual int32_t Open() {
-      return -1;
-    }
-
-    virtual void Close() {
-    }
-
-    virtual int32_t Read(void* buffer, size_t count) {
-      return -1;
-    }
-
-    virtual ~Resource() {
-      free(path_);
-    }
-
-  protected:
-    char* path_;
-    int32_t descriptor_;
-    off_t start_;
-    off_t length_;
-};
-
-#endif  // EMBEDDERS_OPENGLUI_COMMON_RESOURCE_H_
-