Notify the renderer if a history navigation has no subframe items.

content/browser/frame_host/navigation_entry_impl.cc

Index: content/browser/frame_host/navigation_entry_impl.cc
diff --git a/content/browser/frame_host/navigation_entry_impl.cc b/content/browser/frame_host/navigation_entry_impl.cc
index 31b1d508e8ee0a7f70a5fdbc9a28b5e169c5d57e..fbf56542c1609eae1051a8926899c51de2ef4d93 100644
--- a/content/browser/frame_host/navigation_entry_impl.cc
+++ b/content/browser/frame_host/navigation_entry_impl.cc
@@ -691,6 +691,7 @@ RequestNavigationParams NavigationEntryImpl::ConstructRequestNavigationParams(
     const FrameNavigationEntry& frame_entry,
     bool is_same_document_history_load,
     bool is_history_navigation_in_new_child,
+    bool has_subtree_history_items,
     bool has_committed_real_load,
     bool intended_as_new_entry,
     int pending_history_list_offset,
@@ -719,9 +720,9 @@ RequestNavigationParams NavigationEntryImpl::ConstructRequestNavigationParams(
       GetIsOverridingUserAgent(), redirects, GetCanLoadLocalResources(),
       base::Time::Now(), frame_entry.page_state(), GetPageID(), GetUniqueID(),
       is_same_document_history_load, is_history_navigation_in_new_child,
-      has_committed_real_load, intended_as_new_entry, pending_offset_to_send,
-      current_offset_to_send, current_length_to_send, IsViewSourceMode(),
-      should_clear_history_list());
+      has_subtree_history_items, has_committed_real_load, intended_as_new_entry,
+      pending_offset_to_send, current_offset_to_send, current_length_to_send,
+      IsViewSourceMode(), should_clear_history_list());
 #if defined(OS_ANDROID)
   if (GetDataURLAsString() &&
       GetDataURLAsString()->size() <= kMaxLengthOfDataURLString) {
@@ -846,6 +847,12 @@ FrameNavigationEntry* NavigationEntryImpl::GetFrameEntry(
   return tree_node ? tree_node->frame_entry.get() : nullptr;
 }
 
+bool NavigationEntryImpl::HasSubtreeHistoryItems(
+    FrameTreeNode* frame_tree_node) const {
+  NavigationEntryImpl::TreeNode* tree_node = FindFrameEntry(frame_tree_node);
+  return tree_node && !tree_node->children.empty();
+}
+
 void NavigationEntryImpl::ClearStaleFrameEntriesForNewFrame(
     FrameTreeNode* frame_tree_node) {
   DCHECK(!frame_tree_node->IsMainFrame());