[Flare] Adds support for hydrating host components with listeners (#1…

…6304)

packages/react-dom/src/events/__tests__/DOMEventResponderSystem-test.internal.js

@@ -112,6 +112,35 @@ describe('DOMEventResponderSystem', () => {
     expect(output).toBe(`<div data-reactroot="">Hello world</div>`);
   });
 
+  it('can render correctly with the ReactDOMServer hydration', () => {
+    const onEvent = jest.fn();
+    const TestResponder = createEventResponder({
+      targetEventTypes: ['click'],
+      onEvent,
+    });
+    const ref = React.createRef();
+
+    function Test() {
+      const listener = React.unstable_useResponder(TestResponder, {});
+
+      return (
+        <div>
+          <span listeners={listener} ref={ref}>
+            Hello world
+          </span>
+        </div>
+      );
+    }
+    const output = ReactDOMServer.renderToString(<Test />);
+    expect(output).toBe(
+      `<div data-reactroot=""><span>Hello world</span></div>`,
+    );
+    container.innerHTML = output;
+    ReactDOM.hydrate(<Test />, container);
+    dispatchClickEvent(ref.current);
+    expect(onEvent).toHaveBeenCalledTimes(1);
+  });
+
   it('the event responders should fire on click event', () => {
     let eventResponderFiredCount = 0;
     let eventLog = [];

packages/react-reconciler/src/ReactFiberCompleteWork.js

@@ -739,6 +739,18 @@ function completeWork(
             // commit-phase we mark this as such.
             markUpdate(workInProgress);
           }
+          if (enableFlareAPI) {
+            const instance = workInProgress.stateNode;
+            const listeners = newProps.listeners;
+            if (listeners != null) {
+              updateEventListeners(
+                listeners,
+                instance,
+                rootContainerInstance,
+                workInProgress,
+              );
+            }
+          }
         } else {
           let instance = createInstance(
             type,