Remove unused `scope-timeout` module

src/sidebar/util/scope-timeout.js

-/**
- * Sets a timeout which is linked to the lifetime of an Angular scope.
- *
- * When the scope is destroyed, the timeout will be cleared if it has
- * not already fired.
- *
- * The callback is not invoked within a $scope.$apply() context. It is up
- * to the caller to do that if necessary.
- *
- * @param {Scope} $scope - An Angular scope
- * @param {Function} fn - Callback to invoke with setTimeout
- * @param {number} delay - Delay argument to pass to setTimeout
- */
-export default function scopeTimeout(
-  $scope,
-  fn,
-  delay,
-  setTimeoutFn,
-  clearTimeoutFn
-) {
-  setTimeoutFn = setTimeoutFn || setTimeout;
-  clearTimeoutFn = clearTimeoutFn || clearTimeout;
-
-  let removeDestroyHandler;
-  const id = setTimeoutFn(function () {
-    removeDestroyHandler();
-    fn();
-  }, delay);
-  removeDestroyHandler = $scope.$on('$destroy', function () {
-    clearTimeoutFn(id);
-  });
-}

src/sidebar/util/test/scope-timeout-test.js

-import scopeTimeout from '../scope-timeout';
-
-function FakeScope() {
-  this.listeners = {};
-  this.$on = function (event, fn) {
-    this.listeners[event] = this.listeners[event] || [];
-    this.listeners[event].push(fn);
-    return function () {
-      this.listeners[event] = this.listeners[event].filter(function (otherFn) {
-        return otherFn !== fn;
-      });
-    }.bind(this);
-  };
-}
-
-describe('scope-timeout', function () {
-  let fakeSetTimeout;
-  let fakeClearTimeout;
-
-  beforeEach(function () {
-    fakeSetTimeout = sinon.stub().returns(42);
-    fakeClearTimeout = sinon.stub();
-  });
-
-  it('schedules a timeout', function () {
-    const $scope = new FakeScope();
-    const callback = sinon.stub();
-    scopeTimeout($scope, callback, 0, fakeSetTimeout, fakeClearTimeout);
-    assert.calledOnce(fakeSetTimeout);
-    const timeoutFn = fakeSetTimeout.args[0][0];
-    timeoutFn();
-    assert.called(callback);
-  });
-
-  it('removes the scope listener when the timeout fires', function () {
-    const $scope = new FakeScope();
-    const callback = sinon.stub();
-    scopeTimeout($scope, callback, 0, fakeSetTimeout, fakeClearTimeout);
-    assert.equal($scope.listeners.$destroy.length, 1);
-    const timeoutFn = fakeSetTimeout.args[0][0];
-    timeoutFn();
-    assert.equal($scope.listeners.$destroy.length, 0);
-  });
-
-  it('clears the timeout when the scope is destroyed', function () {
-    const $scope = new FakeScope();
-    const callback = sinon.stub();
-    scopeTimeout($scope, callback, 0, fakeSetTimeout, fakeClearTimeout);
-    const destroyFn = $scope.listeners.$destroy[0];
-    destroyFn();
-    assert.calledWith(fakeClearTimeout, 42);
-  });
-});