[compiler] Generalize JSContextSpecialization.

src/compiler/node-properties.h

Index: src/compiler/node-properties.h
diff --git a/src/compiler/node-properties.h b/src/compiler/node-properties.h
index 23253239a12b401fc8f5b7e1aceb998d2fb65541..d428160651294b9155a1f1f677a560a029ce7f41 100644
--- a/src/compiler/node-properties.h
+++ b/src/compiler/node-properties.h
@@ -132,6 +132,11 @@ class V8_EXPORT_PRIVATE NodeProperties final {
   static MaybeHandle<Context> GetSpecializationContext(
       Node* node, MaybeHandle<Context> context = MaybeHandle<Context>());
 
+  // Walk up the context chain from the given {node} until we reduce the {depth}
+  // to 0 or hit a node that does not extend the context chain ({depth} will be
+  // updated accordingly).
+  static Node* GetOuterContext(Node* node, size_t* depth);
+
   // ---------------------------------------------------------------------------
   // Type.