Fix for the NavigationControllerTest.BackSubframe test failures with PlzNavigate

content/public/common/page_state.h

Index: content/public/common/page_state.h
diff --git a/content/public/common/page_state.h b/content/public/common/page_state.h
index c38f961bb24d4bccdca34465292cbe130ca36c1f..6cf6c09116e7fba802190cbae64d2a393689b0a4 100644
--- a/content/public/common/page_state.h
+++ b/content/public/common/page_state.h
@@ -35,6 +35,13 @@ class CONTENT_EXPORT PageState {
       const char* optional_body_data,
       const base::FilePath* optional_body_file_path);
 
+  // Creates an encoded page state from the |url|, |item_sequence_mnumber| and
+  // |document_sequence_number| parameters.
+  static PageState CreateForTestingWithSequenceNumbers(
+      const GURL& url,
+      int64_t item_sequence_number,
+      int64_t document_sequence_number);
+
   PageState();
 
   bool IsValid() const;