Remove openglui embedder code

runtime/embedders/openglui/common/support.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_SUPPORT_H_
-#define EMBEDDERS_OPENGLUI_COMMON_SUPPORT_H_
-
-#include "embedders/openglui/common/opengl.h"
-
-#ifndef MAX
-#define MAX(a, b) (((a) > (b)) ? (a) : (b))
-#endif
-#ifndef MIN
-#define MIN(a, b) (((a) < (b)) ? (a) : (b))
-#endif
-
-// Colors as used by canvas.
-typedef struct ColorRGBA {
-  // We store Skia-compatible values. Skia uses
-  // the form AARRGGBB.
-  uint32_t v;
-
-  inline ColorRGBA(char rp, char gp, char bp, char ap = 255) {
-    v = ((static_cast<uint32_t>(rp) & 0xFF) << 16) |
-        ((static_cast<uint32_t>(gp) & 0xFF) << 8) |
-        ((static_cast<uint32_t>(bp) & 0xFF) << 0) |
-        ((static_cast<uint32_t>(ap) & 0xFF) << 24);
-  }
-  inline ColorRGBA(uint32_t vp)
-    : v(vp) {
-  }
-  inline uint8_t alpha() {
-    return (v >> 24) & 0xFF;
-  }
-} ColorRGBA;
-
-#endif  // EMBEDDERS_OPENGLUI_COMMON_SUPPORT_H_