anchor.diff:  
   /// The highest WebGL version supported by the current browser, or -1 if WebGL
   /// is not supported.
  -int get webGLVersion => _cachedWebGLVersion ?? (_cachedWebGLVersion = _detectWebGLVersion());
  +int get webGLVersion =>
  +    _cachedWebGLVersion ?? (_cachedWebGLVersion = _detectWebGLVersion());
   
   /// Detects the highest WebGL version supported by the current browser, or
   /// -1 if WebGL is not supported.
  
positive.code: ///    Note: SAMSUNG-SGH-I717
  ///    SPH/SCH are very old Palm models.
  bool _isSamsungBrowser(String agent) {
    final RegExp exp = RegExp(r'SAMSUNG|SGH-[I|N|T]|GT-[I|N]|SM-[A|N|P|T|Z]|SHV-E|SCH-[I|J|R|S]|SPH-L');
    return exp.hasMatch(agent.toUpperCase());
  }
  
  
negative.code: abstract class WebGLVersion {
    /// WebGL 1.0 is based on OpenGL ES 2.0 / GLSL 1.00
    static const int webgl1 = 1;
  
    /// WebGL 2.0 is based on OpenGL ES 3.0 / GLSL 3.00
    static const int webgl2 = 2;
  }
  