diff --git a/lib/ui/semantics.dart b/lib/ui/semantics.dart
index 1e3650910d543390866f54d3e68eee6916de761c..79aaf1ef943d9d608e5a588650fd9b6e2604061e 100644
--- a/lib/ui/semantics.dart
+++ b/lib/ui/semantics.dart
@@ -264,8 +264,9 @@ class SemanticsAction {
 
 /// A Boolean value that can be associated with a semantics node.
 //
-// When changes are made to this class, the equivalent APIs in each of the
-// embedders *must* be updated.
+// When changes are made to this class, the equivalent APIs in
+// `lib/ui/semantics/semantics_node.h` and in each of the embedders *must* be
+// updated.
 class SemanticsFlag {
   static const int _kHasCheckedStateIndex = 1 << 0;
   static const int _kIsCheckedIndex = 1 << 1;
@@ -476,9 +477,9 @@ class SemanticsFlag {
   /// to move focus to an offscreen child.
   ///
   /// For example, a [ListView] widget has implicit scrolling so that users can
-  /// easily move to the next visible set of children. A [TabBar] widget does
-  /// not have implicit scrolling, so that users can navigate into the tab
-  /// body when reaching the end of the tab bar.
+  /// easily move the accessibility focus to the next set of children. A
+  /// [PageView] widget does not have implicit scrolling, so that users don't
+  /// navigate to the next page when reaching the end of the current one.
   static const SemanticsFlag hasImplicitScrolling = const SemanticsFlag._(_kHasImplicitScrollingIndex);
 
   /// The possible semantics flags.
diff --git a/lib/ui/semantics/semantics_node.h b/lib/ui/semantics/semantics_node.h
index 7596dc20957e8b22db8b7b7a2394f8a52608a652..6bed3b305f1d309d0cca9bbca2c5fcc455fe842c 100644
--- a/lib/ui/semantics/semantics_node.h
+++ b/lib/ui/semantics/semantics_node.h
@@ -65,6 +65,7 @@ enum class SemanticsFlags : int32_t {
   kIsLiveRegion = 1 << 15,
   kHasToggledState = 1 << 16,
   kIsToggled = 1 << 17,
+  kHasImplicitScrolling = 1 << 18,
 };
 
 struct SemanticsNode {
diff --git a/shell/platform/embedder/embedder.h b/shell/platform/embedder/embedder.h
index baf789594d0120be414dc857d0b48f93eece7df1..11f70f1092f5dc31661630eb8fe9563a51c59caa 100644
--- a/shell/platform/embedder/embedder.h
+++ b/shell/platform/embedder/embedder.h
@@ -141,6 +141,14 @@ typedef enum {
   kFlutterSemanticsFlagHasToggledState = 1 << 16,
   // If true, the semantics node is "on". If false, the semantics node is "off".
   kFlutterSemanticsFlagIsToggled = 1 << 17,
+  // Whether the platform can scroll the semantics node when the user attempts
+  // to move the accessibility focus to an offscreen child.
+  //
+  // For example, a |ListView| widget has implicit scrolling so that users can
+  // easily move the accessibility focus to the next set of children. A
+  // |PageView| widget does not have implicit scrolling, so that users don't
+  // navigate to the next page when reaching the end of the current one.
+  kFlutterSemanticsFlagHasImplicitScrolling = 1 << 18,
 } FlutterSemanticsFlag;
 
 typedef enum {