DevTools: useModalDismissSignal bugfix (facebook#21173)

* DevTools: useModalDismissSignal bugfix

Make useModalDismissSignal's manually added click/keyboard events more robust to sync flushed passive effects. (Don't let the same click event that shows a modal dialog also dismiss it.)

* Replaced event.timeStamp check with setTimeout

packages/react-devtools-shared/src/devtools/views/hooks.js

@@ -207,14 +207,13 @@ export function useModalDismissSignal(
       return () => {};
     }
 
-    const handleDocumentKeyDown = ({key}: any) => {
-      if (key === 'Escape') {
+    const handleDocumentKeyDown = (event: any) => {
+      if (event.key === 'Escape') {
         dismissCallback();
       }
     };
 
     const handleDocumentClick = (event: any) => {
-      // $FlowFixMe
       if (
         modalRef.current !== null &&
         !modalRef.current.contains(event.target)
@@ -226,18 +225,33 @@ export function useModalDismissSignal(
       }
     };
 
-    // It's important to listen to the ownerDocument to support the browser extension.
-    // Here we use portals to render individual tabs (e.g. Profiler),
-    // and the root document might belong to a different window.
-    const ownerDocument = modalRef.current.ownerDocument;
-    ownerDocument.addEventListener('keydown', handleDocumentKeyDown);
-    if (dismissOnClickOutside) {
-      ownerDocument.addEventListener('click', handleDocumentClick);
-    }
+    let ownerDocument = null;
+
+    // Delay until after the current call stack is empty,
+    // in case this effect is being run while an event is currently bubbling.
+    // In that case, we don't want to listen to the pre-existing event.
+    let timeoutID = setTimeout(() => {
+      timeoutID = null;
+
+      // It's important to listen to the ownerDocument to support the browser extension.
+      // Here we use portals to render individual tabs (e.g. Profiler),
+      // and the root document might belong to a different window.
+      ownerDocument = ((modalRef.current: any): HTMLDivElement).ownerDocument;
+      ownerDocument.addEventListener('keydown', handleDocumentKeyDown);
+      if (dismissOnClickOutside) {
+        ownerDocument.addEventListener('click', handleDocumentClick);
+      }
+    }, 0);
 
     return () => {
-      ownerDocument.removeEventListener('keydown', handleDocumentKeyDown);
-      ownerDocument.removeEventListener('click', handleDocumentClick);
+      if (timeoutID !== null) {
+        clearTimeout(timeoutID);
+      }
+
+      if (ownerDocument !== null) {
+        ownerDocument.removeEventListener('keydown', handleDocumentKeyDown);
+        ownerDocument.removeEventListener('click', handleDocumentClick);
+      }
     };
   }, [modalRef, dismissCallback, dismissOnClickOutside]);
 }