loadShader_(type, shaderSrc) {
    const gl = this.gl_;
    const shader = gl.createShader(type);
    // Load the shader source
    gl.shaderSource(shader, shaderSrc);
    // Compile the shader
    gl.compileShader(shader);
    // Check the compile status
    if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
      const infoLog = gl.getShaderInfoLog(shader);
      gl.deleteShader(shader);
      throw new Error(`Error compiling shader:\n${infoLog}`);
    }
    return shader;
  }
Creates and compiles a WebGLShader from the provided source code.
@param {number} type either VERTEX_SHADER or FRAGMENT_SHADER
@param {string} shaderSrc
@return {!WebGLShader}
@private