Don't fire onbeforeunload for same document history navigations with PlzNavigate.

content/test/test_render_frame_host.cc

Index: content/test/test_render_frame_host.cc
diff --git a/content/test/test_render_frame_host.cc b/content/test/test_render_frame_host.cc
index c7d0d6f4bca4d3bf1935e3a48be416d0fa7b2a34..2c98841e74c1d30e285e40394f166a4a6c659059 100644
--- a/content/test/test_render_frame_host.cc
+++ b/content/test/test_render_frame_host.cc
@@ -325,8 +325,10 @@ void TestRenderFrameHost::SendNavigateWithParameters(
   params.history_list_was_cleared = simulate_history_list_was_cleared_;
   params.original_request_url = url_copy;
 
-  // Simulate Blink assigning an item sequence number to the navigation.
+  // Simulate Blink assigning an item and document sequence number to the
+  // navigation.
   params.item_sequence_number = base::Time::Now().ToDoubleT() * 1000000;
+  params.document_sequence_number = params.item_sequence_number + 1;
 
   // When the user hits enter in the Omnibox without changing the URL, Blink
   // behaves similarly to a reload and does not change the item and document
@@ -368,7 +370,9 @@ void TestRenderFrameHost::SendNavigateWithParameters(
            GetLastCommittedURL().ReplaceComponents(replacements));
 
   params.page_state =
-      PageState::CreateForTesting(url_copy, false, nullptr, nullptr);
+      PageState::CreateForTestingWithSequenceNumbers(
+          url_copy, params.item_sequence_number,
+          params.document_sequence_number);
 
   if (!callback.is_null())
     callback.Run(&params);