Fix for the NavigationControllerTest.BackSubframe test failures with PlzNavigate

content/public/common/page_state.cc

Index: content/public/common/page_state.cc
diff --git a/content/public/common/page_state.cc b/content/public/common/page_state.cc
index 01cbedbedb7a394d39a81aa9d5b06f832c593259..7f9dfddfd0fd3148f14837aec80a28ebfcb34f35 100644
--- a/content/public/common/page_state.cc
+++ b/content/public/common/page_state.cc
@@ -105,6 +105,21 @@ PageState PageState::CreateForTesting(
   return ToPageState(state);
 }
 
+// static
+PageState PageState::CreateForTestingWithSequenceNumbers(
+    const GURL& url,
+    int64_t item_sequence_number,
+    int64_t document_sequence_number) {
+  ExplodedPageState page_state;
+  page_state.top.url_string = ToNullableString16(url.spec());
+  page_state.top.item_sequence_number = item_sequence_number;
+  page_state.top.document_sequence_number = document_sequence_number;
+
+  std::string encoded_page_state;
+  EncodePageState(page_state, &encoded_page_state);
+  return CreateFromEncodedData(encoded_page_state);
+}
+
 PageState::PageState() {
 }