Remove openglui embedder code

runtime/embedders/openglui/common/opengl.h

-// Copyright (c) 2013, 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.
-
-// A semi-generic header file that can be used to isolate platform differences
-// for OpenGL headers.
-#ifndef EMBEDDERS_OPENGLUI_COMMON_OPENGL_H_
-#define EMBEDDERS_OPENGLUI_COMMON_OPENGL_H_
-
-#if defined(__APPLE__)
-#  ifdef GL_ES_VERSION_2_0
-#    include <OpenGLES/ES2/gl.h>
-#  else
-#    include <Glut/glut.h>
-#    include <OpenGL/gl.h>
-#  endif
-#  define GLSwapBuffers()    glutSwapBuffers()
-#elif defined(_WIN32) || defined(_WIN64)
-#  include <GL/glew.h>
-#  include <GL/wglew.h>
-#  include <GLUT/glut.h>
-#  include <Windows.h>
-#  define GLSwapBuffers()    glutSwapBuffers()
-#elif defined(__ANDROID__)
-#  include <EGL/egl.h>
-#  include <GLES2/gl2.h>
-#  include <GLES2/gl2ext.h>
-#  define GLSwapBuffers() \
-    do {\
-      EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY); \
-      EGLSurface surface = eglGetCurrentSurface(EGL_DRAW); \
-      eglSwapBuffers(display, surface); \
-    } while (0);
-#else  // Linux.
-#  define GL_GLEXT_PROTOTYPES 1
-#  include <GL/gl.h>
-#  include <GL/glext.h>
-#  include <GL/glut.h>
-#  define GLSwapBuffers()    glutSwapBuffers()
-#endif
-
-#include "core/SkCanvas.h"
-#include "core/SkGraphics.h"
-#include "core/SkPaint.h"
-#include "core/SkTypeface.h"
-#include "effects/SkBlurDrawLooper.h"
-#include "effects/SkDashPathEffect.h"
-#include "effects/SkGradientShader.h"
-#include "gpu/SkGpuDevice.h"
-#include "gpu/GrContext.h"
-#include "gpu/GrRenderTarget.h"
-#include "gpu/gl/GrGLInterface.h"
-#include "gpu/gl/SkNativeGLContext.h"
-#include "images/SkImageDecoder.h"
-
-#endif  // EMBEDDERS_OPENGLUI_COMMON_OPENGL_H_
-