constructor() {
    // All fields are initialized in init()
    /** @private {?OffscreenCanvas} canvas used to create the WebGL context */
    this.canvas_ = null;
    /** @private {?WebGLRenderingContext} */
    this.gl_ = null;
    /** @private {?WebGLUniformLocation} location of inSampler */
    this.sampler_ = null;
    /** @private {?WebGLProgram} */
    this.program_ = null;
    /** @private {?WebGLTexture} input texture */
    this.texture_ = null;
    /** @private {string} */
    this.debugPath_ = 'debug.pipeline.frameTransform_';
  }
Applies a warp effect using WebGL.
@implements {FrameTransform} in pipeline.js