Looks like these functions don't work at all:

  void uniform1uiv(WebGLUniformLocation? location, Uint32List data, optional GLuint srcOffset = 0,
                  optional GLuint srcLength = 0);
  void uniform2uiv(WebGLUniformLocation? location, Uint32List data, optional GLuint srcOffset = 0,
                  optional GLuint srcLength = 0);
  void uniform3uiv(WebGLUniformLocation? location, Uint32List data, optional GLuint srcOffset = 0,
                  optional GLuint srcLength = 0);
  void uniform4uiv(WebGLUniformLocation? location, Uint32List data, optional GLuint srcOffset = 0,
                  optional GLuint srcLength = 0);
  void uniformMatrix3x2fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);
  void uniformMatrix4x2fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);

  void uniformMatrix2x3fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);
  void uniformMatrix4x3fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);

  void uniformMatrix2x4fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);
  void uniformMatrix3x4fv(WebGLUniformLocation? location, GLboolean transpose, Float32List data,
                          optional GLuint srcOffset = 0, optional GLuint srcLength = 0);