code: function instrumentExtensionObject(ctx, name, object) {
      var proto = object.constructor.prototype;
  
      // We do this check only for known extensions, as Firefox will return a
      // generic 'Object' for others and that will break everything.
      function checkInstrumented() {
        if (proto['__gl_wrapped__']) {
          return false;
        }
        Object.defineProperty(proto, '__gl_wrapped__', {
          'configurable': true,
          'enumerable': false,
          'value': true
        });
        contextRestoreFns.push(function() {
          delete proto['__gl_wrapped__'];
        });
        return true;
      };
  
      switch (name) {
        case 'ANGLE_instanced_arrays':
          if (checkInstrumented()) {
            wrapInstancedArraysExtension(ctx, proto);
          }
          return true;
        case 'OES_vertex_array_object':
          if (checkInstrumented()) {
            wrapVertexArrayObjectExtension(ctx, proto);
          }
          return true;
        case 'WEBGL_lose_context':
          if (checkInstrumented()) {
            wrapLoseContextExtension(ctx, proto);
          }
          return true;
        case 'WEBGL_draw_buffers':
          // http://www.khronos.org/registry/webgl/extensions/WEBGL_draw_buffers/
        case 'WEBGL_security_sensitive_resources':
          // http://www.khronos.org/registry/webgl/extensions/WEBGL_security_sensitive_resources/
        case 'WEBGL_shared_resources':
          // http://www.khronos.org/registry/webgl/extensions/WEBGL_shared_resources/
          // Don't support these yet, so report them as not present.
          return false;
        default:
          return true;
      }
    }
docs: Wraps an extension object.
  This should be called for each extension object as it is returned from
  getExtension so that its prototype can be instrumented, as required.
  @param {!WebGLRenderingContext} ctx Target context.
  @param {string} name Extension name.
  @param {!Object} object Extension object.
  @return {boolean} True if the extension is supported.