Suspend the commit while we wait for the previous transition to finish

Author: sebmarkbage

packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js

@@ -1197,8 +1197,14 @@ export function startViewTransition(
     // TODO: Wait for fonts.
     afterMutationCallback();
   });
+  // $FlowFixMe[prop-missing]
+  ownerDocument.__reactViewTransition = transition;
   transition.ready.then(layoutCallback, layoutCallback);
-  transition.finished.then(passiveCallback);
+  transition.finished.then(() => {
+    // $FlowFixMe[prop-missing]
+    ownerDocument.__reactViewTransition = null;
+    passiveCallback();
+  });
   return true;
 }
 
@@ -3681,6 +3687,19 @@ export function suspendOnActiveViewTransition(rootContainer: Container): void {
       'Internal React Error: suspendedState null when it was expected to exists. Please report this as a React bug.',
     );
   }
+  const state = suspendedState;
+  const ownerDocument =
+    rootContainer.nodeType === DOCUMENT_NODE
+      ? rootContainer
+      : rootContainer.ownerDocument;
+  // $FlowFixMe[prop-missing]
+  const activeViewTransition = ownerDocument.__reactViewTransition;
+  if (activeViewTransition == null) {
+    return;
+  }
+  state.count++;
+  const ping = onUnsuspend.bind(state);
+  activeViewTransition.finished.then(ping, ping);
 }
 
 export function waitForCommitToBeReady(): null | ((() => void) => () => void) {