diff --git a/internal/controller/form-controller.ts b/internal/controller/form-controller.ts
deleted file mode 100644
index bb3005af4c..0000000000
--- a/internal/controller/form-controller.ts
+++ /dev/null
@@ -1,109 +0,0 @@
-/**
- * @license
- * Copyright 2021 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import {ReactiveController, ReactiveControllerHost} from 'lit';
-
-declare global {
-  interface Window {
-    ShadyDOM?: {inUse: boolean;};
-  }
-}
-
-/**
- * An element that `FormController` may use.
- */
-export interface FormElement extends ReactiveControllerHost, HTMLElement {
-  /**
-   * The `<form>` that this element is associated with.
-   */
-  readonly form: HTMLFormElement|null;
-  /**
-   * The name of the element in the form. This property should reflect to a
-   * `name` attribute.
-   */
-  name: string;
-  /**
-   * Whether or not this element is disabled. If present, this property should
-   * reflect to a `disabled` attribute.
-   */
-  disabled?: boolean;
-  /**
-   * A function that retrieves the current form value for this element.
-   *
-   * @return The current form value, or `null` if there is no value.
-   */
-  [getFormValue](): string|File|FormData|null;
-}
-
-/**
- * A unique symbol key for `FormController` elements to implement their
- * `getFormValue()` function.
- */
-export const getFormValue = Symbol('getFormValue');
-
-/**
- * A `ReactiveController` that adds `<form>` support to an element.
- *
- * Elements should also set `static formAssociated = true` which
- * provides platform support for forms. When an element is form associated,
- * it can be activated via clicks on associated label elements. It is the
- * responsibility of the element to process this click and perform any necessary
- * activation tasks, for example focusing and clicking on an internal element.
- *
- */
-export class FormController implements ReactiveController {
-  private form?: HTMLFormElement|null;
-
-  /**
-   * Creates a new `FormController` for the given element.
-   *
-   * @param element The element to add `<form>` support to.
-   */
-  constructor(private readonly element: FormElement) {}
-
-  hostConnected() {
-    // If the component internals are not in Shadow DOM, subscribing to form
-    // data events could lead to duplicated data, which may not work correctly
-    // on the server side.
-    if (!this.element.shadowRoot || window.ShadyDOM?.inUse) {
-      return;
-    }
-
-    // Preserve a reference to the form, since on hostDisconnected it may be
-    // null if the child was removed.
-    this.form = this.element.form;
-    this.form?.addEventListener('formdata', this.formDataListener);
-  }
-
-  hostDisconnected() {
-    this.form?.removeEventListener('formdata', this.formDataListener);
-  }
-
-  private readonly formDataListener = (event: FormDataEvent) => {
-    if (this.element.disabled) {
-      // Check for truthiness since some elements may not support disabling.
-      return;
-    }
-
-    const value = this.element[getFormValue]();
-    // If given a `FormData` instance, append all values to the form. This
-    // allows elements to customize what is added beyond a single name/value
-    // pair.
-    if (value instanceof FormData) {
-      for (const [key, dataValue] of value) {
-        event.formData.append(key, dataValue);
-      }
-      return;
-    }
-
-    // Do not associate the value with the form if there is no value or no name.
-    if (value === null || !this.element.name) {
-      return;
-    }
-
-    event.formData.append(this.element.name, value);
-  };
-}
diff --git a/internal/controller/form-controller_test.ts b/internal/controller/form-controller_test.ts
deleted file mode 100644
index 26ce29f77f..0000000000
--- a/internal/controller/form-controller_test.ts
+++ /dev/null
@@ -1,331 +0,0 @@
-/**
- * @license
- * Copyright 2021 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-// import 'jasmine'; (google3-only)
-
-import {html, LitElement, TemplateResult} from 'lit';
-import {customElement, property, query} from 'lit/decorators.js';
-
-import {Environment} from '../../testing/environment.js';
-import {Harness} from '../../testing/harness.js';
-
-import {dispatchActivationClick, isActivationClick} from './events.js';
-import {FormController, FormElement, getFormValue} from './form-controller.js';
-
-declare global {
-  interface HTMLElementTagNameMap {
-    'my-form-element': MyFormElement;
-    'my-form-data-element': MyFormDataElement;
-    'my-checked-form-element': MyCheckedFormElement;
-    'my-checked-form-associated-element': MyCheckedFormAssociatedElement;
-  }
-}
-
-@customElement('my-form-element')
-class MyFormElement extends LitElement implements FormElement {
-  get form() {
-    return this.closest('form');
-  }
-  @property({type: Boolean}) disabled = false;
-  @property() name = '';
-  @property() value = '';
-  [getFormValue](): string|null|FormData {
-    return this.value ? this.value : null;
-  }
-
-  constructor() {
-    super();
-    this.addController(new FormController(this));
-  }
-}
-
-@customElement('my-form-data-element')
-class MyFormDataElement extends MyFormElement {
-  override[getFormValue]() {
-    const data = new FormData();
-    data.append('element-value', this.value);
-    data.append('element-foo', 'foo');
-    return data;
-  }
-}
-
-@customElement('my-checked-form-element')
-class MyCheckedFormElement extends MyFormElement {
-  @property({type: Boolean}) checked = false;
-
-  @query('#checked') checkedEl!: HTMLDivElement|null;
-
-  constructor() {
-    super();
-    this.setupActivationClickHandler();
-  }
-
-  setupActivationClickHandler() {
-    this.addEventListener('click', (event: MouseEvent) => {
-      if (!isActivationClick(event) || !this.checkedEl) {
-        return;
-      }
-      this.checkedEl.focus();
-      dispatchActivationClick(this.checkedEl);
-    });
-  }
-
-  // Note, due to the following Firefox issue, it's important that the
-  // element contain native "interactive content" like a button or input,
-  // see https://bugzilla.mozilla.org/show_bug.cgi?id=1804576.
-  //
-  protected override render() {
-    return html`<button id="checked" @click=${
-        () => this.checked = !this.checked}>
-      ${this.checked}
-    </button>`;
-  }
-
-  override focus() {
-    this.checkedEl?.focus();
-  }
-}
-
-@customElement('my-checked-form-associated-element')
-class MyCheckedFormAssociatedElement extends MyCheckedFormElement {
-  static formAssociated = true;
-}
-
-class CheckedFormElementHarness extends Harness<MyCheckedFormElement> {
-  protected override async getInteractiveElement() {
-    await this.element.updateComplete;
-    return this.element.checkedEl!;
-  }
-}
-
-describe('FormController', () => {
-  const env = new Environment();
-
-  async function setupTest(template: TemplateResult) {
-    const root = env.render(html`
-      <form>${template}</form>
-    `);
-
-    await env.waitForStability();
-    const element =
-        root.querySelector('form')!.firstElementChild! as HTMLElement;
-    return new Harness(element);
-  }
-
-  it('should add element\'s name/value pair to the form', async () => {
-    const harness = await setupTest(html`
-      <my-form-element name="element" value="foo"></my-form-element>
-    `);
-    const data = await harness.submitForm();
-    expect(data.has('element'))
-        .withContext('should add name to data')
-        .toBeTrue();
-    expect(data.get('element'))
-        .withContext('should add value to data')
-        .toBe('foo');
-  });
-
-  it('should add form associated element\'s name/value pair to the form',
-     async () => {
-       const harness = await setupTest(html`
-        <my-checked-form-associated-element name="element" value="foo">
-        </my-checked-form-associated-element>`);
-
-       const data = await harness.submitForm();
-       expect(data.has('element'))
-           .withContext('should add name to data')
-           .toBeTrue();
-       expect(data.get('element'))
-           .withContext('should add value to data')
-           .toBe('foo');
-     });
-
-  it('should not add data when disconnected', async () => {
-    const harness = await setupTest(html`
-      <my-form-element name="element" value="foo"></my-form-element>
-    `);
-
-    const form = harness.element.form!;
-    harness.element.remove();
-    expect(harness.element.form).toBeNull();
-    const data = await harness.submitForm(form);
-    expect(data.has('element'))
-        .withContext('should not add disconnected element to data')
-        .toBeFalse();
-  });
-
-  it('should not add data when element is disabled', async () => {
-    const harness = await setupTest(html`
-      <my-form-element name="element" value="foo" disabled></my-form-element>
-    `);
-
-    const data = await harness.submitForm();
-    expect(data.has('element'))
-        .withContext('should not add disabled element to data')
-        .toBeFalse();
-  });
-
-  it('should not add data when value is null', async () => {
-    const harness = await setupTest(html`
-      <my-form-element name="element"></my-form-element>
-    `);
-
-    const data = await harness.submitForm();
-    expect(data.has('element'))
-        .withContext('should not add null value to data')
-        .toBeFalse();
-  });
-
-  it('should add all entries if element returns FormData', async () => {
-    const harness = await setupTest(html`
-      <my-form-data-element value="foo"></my-form-data-element>
-    `);
-
-    const data = await harness.submitForm();
-    expect(data.has('element-value'))
-        .withContext('should add element-value data')
-        .toBe(true);
-    expect(data.has('element-foo'))
-        .withContext('should add element-value data')
-        .toBe(true);
-    expect(data.get('element-value'))
-        .withContext('element-value should match data value')
-        .toBe('foo');
-    expect(data.get('element-foo'))
-        .withContext('element-foo should match "foo"')
-        .toBe('foo');
-  });
-
-  describe('label activation', () => {
-    const setupLabelTest = async (
-        template: TemplateResult,
-        harnessTag = 'my-checked-form-associated-element') => {
-      const root = env.render(html`
-        <form>${template}</form>
-      `);
-      await env.waitForStability();
-      const label = new Harness(root.querySelector<HTMLLabelElement>('label')!);
-      const face = new CheckedFormElementHarness(
-          root.querySelector<MyCheckedFormElement>(harnessTag)!);
-      return {label, face};
-    };
-
-    it('should activate via click event', async () => {
-      const {face} = await setupLabelTest(html`
-        <label>
-          <my-checked-form-associated-element value="foo">
-          </my-checked-form-associated-element>
-        </label>
-      `);
-      expect(face.element.checked).toBeFalse();
-      await face.clickWithMouse();
-      expect(face.element.checked).toBeTrue();
-      await face.clickWithMouse();
-      expect(face.element.checked).toBeFalse();
-    });
-
-    it('should activate via click method', async () => {
-      const {face} = await setupLabelTest(html`
-        <label>
-          <my-checked-form-associated-element value="foo">
-          </my-checked-form-associated-element>
-        </label>
-      `);
-      expect(face.element.checked).toBeFalse();
-      face.element.click();
-      await env.waitForStability();
-      expect(face.element.checked).toBeTrue();
-      face.element.click();
-      await env.waitForStability();
-      expect(face.element.checked).toBeFalse();
-    });
-
-    it('should activate form associated elements via surrounding label',
-       async () => {
-         const {label, face} = await setupLabelTest(html`
-          <label>
-            label
-            <my-checked-form-associated-element value="foo">
-            </my-checked-form-associated-element>
-          </label>`);
-         expect(face.element.checked).toBeFalse();
-         await face.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeFalse();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-       });
-
-    it('should not generate extra clicks when activated', async () => {
-      const {label, face} = await setupLabelTest(html`
-        <label>
-          <my-checked-form-associated-element value="foo">
-          </my-checked-form-associated-element>
-        </label>`);
-      expect(face.element.checked).toBeFalse();
-      const clickListener = jasmine.createSpy('clickListener');
-      face.element.addEventListener('click', clickListener);
-      await face.clickWithMouse();
-      expect(clickListener).toHaveBeenCalledTimes(1);
-      face.element.click();
-      await env.waitForStability();
-      expect(clickListener).toHaveBeenCalledTimes(2);
-      await label.clickWithMouse();
-      expect(clickListener).toHaveBeenCalledTimes(3);
-    });
-
-    it('should activate form associated elements via label with matching `for`',
-       async () => {
-         const {label, face} = await setupLabelTest(html`
-          <label for="a">a</label>
-          <my-checked-form-associated-element id="a" value="foo">
-          </my-checked-form-associated-element>`);
-         expect(face.element.checked).toBeFalse();
-         await face.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeFalse();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-
-         // Disconnect `for` and check that face is not activated.
-         label.element.setAttribute('for', '');
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-       });
-
-    it('should *not* activate disabled form associated elements via label',
-       async () => {
-         const {label, face} = await setupLabelTest(html`
-          <label>
-            label
-            <my-checked-form-associated-element disabled value="foo">
-            </my-checked-form-associated-element>
-          </label>`);
-         expect(face.element.checked).toBeFalse();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeFalse();
-       });
-
-    it('should *not* activate non-form associated elements via label',
-       async () => {
-         const {label, face} = await setupLabelTest(
-             html`
-          <label>
-            label
-            <my-checked-form-element value="foo">
-            </my-checked-form-element>
-          </label>`,
-             `my-checked-form-element`);
-         expect(face.element.checked).toBeFalse();
-         await face.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-         await label.clickWithMouse();
-         expect(face.element.checked).toBeTrue();
-       });
-  });
-});