[DevTools] Synchronize Scroll Position Between Suspense Tab and Main Document (facebook#34641)

It's annoying to have to try to find where it lines up with no hints.

This way when you hover over something it should be on screen.

The strategy I went with is that it scrolls to a percentage along the
scrollable axis but the two might not be exactly the same. Partially
because they have different aspect ratios but also because suspended
boundaries can shrink the document while the suspense tab needs to still
be able to show the boundaries that are currently invisible.

DiffTrain build for [3a0ab8a](facebook@3a0ab8a)

Author: pull[bot]

compiled-rn/VERSION_NATIVE_FB

@@ -1 +1 @@
-19.3.0-native-fb-408b38ef-20251023
+19.3.0-native-fb-3a0ab8a7-20251029

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-dev.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<7091fabeff3133a034d503a8010cc2c6>>
+ * @generated SignedSource<<2fa4486f02e27cc504aee043bf8a14cb>>
  */
 
 "use strict";
@@ -126,10 +126,20 @@ __DEV__ &&
         throw Error("Target container is not a DOM element.");
       return createPortal$1(children, container, null, key);
     };
-    exports.flushSync = function () {
-      throw Error(
-        "Expected this build of React to not support legacy mode but it does. This is a bug in React."
-      );
+    exports.flushSync = function (fn) {
+      var previousTransition = ReactSharedInternals.T,
+        previousUpdatePriority = Internals.p;
+      try {
+        if (((ReactSharedInternals.T = null), (Internals.p = 2), fn))
+          return fn();
+      } finally {
+        (ReactSharedInternals.T = previousTransition),
+          (Internals.p = previousUpdatePriority),
+          Internals.d.f() &&
+            console.error(
+              "flushSync was called from inside a lifecycle method. React cannot flush when React is already rendering. Consider moving this call to a scheduler task or micro task."
+            );
+      }
     };
     exports.preconnect = function (href, options) {
       "string" === typeof href && href
@@ -404,5 +414,5 @@ __DEV__ &&
     exports.useFormStatus = function () {
       return resolveDispatcher().useHostTransitionStatus();
     };
-    exports.version = "19.3.0-native-fb-408b38ef-20251023";
+    exports.version = "19.3.0-native-fb-3a0ab8a7-20251029";
   })();

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-prod.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<c2fa393bfca5ed623ddafb57633dea03>>
+ * @generated SignedSource<<a640364eab7add93b41d4111387f9d1c>>
  */
 
 "use strict";
@@ -78,10 +78,16 @@ exports.createPortal = function (children, container) {
     throw Error(formatProdErrorMessage(299));
   return createPortal$1(children, container, null, key);
 };
-exports.flushSync = function () {
-  throw Error(
-    "Expected this build of React to not support legacy mode but it does. This is a bug in React."
-  );
+exports.flushSync = function (fn) {
+  var previousTransition = ReactSharedInternals.T,
+    previousUpdatePriority = Internals.p;
+  try {
+    if (((ReactSharedInternals.T = null), (Internals.p = 2), fn)) return fn();
+  } finally {
+    (ReactSharedInternals.T = previousTransition),
+      (Internals.p = previousUpdatePriority),
+      Internals.d.f();
+  }
 };
 exports.preconnect = function (href, options) {
   "string" === typeof href &&
@@ -203,4 +209,4 @@ exports.useFormState = function (action, initialState, permalink) {
 exports.useFormStatus = function () {
   return ReactSharedInternals.H.useHostTransitionStatus();
 };
-exports.version = "19.3.0-native-fb-408b38ef-20251023";
+exports.version = "19.3.0-native-fb-3a0ab8a7-20251029";

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-profiling.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<c2fa393bfca5ed623ddafb57633dea03>>
+ * @generated SignedSource<<a640364eab7add93b41d4111387f9d1c>>
  */
 
 "use strict";
@@ -78,10 +78,16 @@ exports.createPortal = function (children, container) {
     throw Error(formatProdErrorMessage(299));
   return createPortal$1(children, container, null, key);
 };
-exports.flushSync = function () {
-  throw Error(
-    "Expected this build of React to not support legacy mode but it does. This is a bug in React."
-  );
+exports.flushSync = function (fn) {
+  var previousTransition = ReactSharedInternals.T,
+    previousUpdatePriority = Internals.p;
+  try {
+    if (((ReactSharedInternals.T = null), (Internals.p = 2), fn)) return fn();
+  } finally {
+    (ReactSharedInternals.T = previousTransition),
+      (Internals.p = previousUpdatePriority),
+      Internals.d.f();
+  }
 };
 exports.preconnect = function (href, options) {
   "string" === typeof href &&
@@ -203,4 +209,4 @@ exports.useFormState = function (action, initialState, permalink) {
 exports.useFormStatus = function () {
   return ReactSharedInternals.H.useHostTransitionStatus();
 };
-exports.version = "19.3.0-native-fb-408b38ef-20251023";
+exports.version = "19.3.0-native-fb-3a0ab8a7-20251029";