Create FrameNavigationEntries for manual subframe navigations.

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 5d4dee8bb4f528239f5aa090c019182e197bf25f..0491cfb0794e3e3b497d048ce104a8d52b42f3e6 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -1393,7 +1393,21 @@ void NavigationControllerImpl::RendererDidNavigateNewSubframe(
   // band with the actual navigations.
   DCHECK(GetLastCommittedEntry()) << "ClassifyNavigation should guarantee "
                                   << "that a last committed entry exists.";
-  NavigationEntryImpl* new_entry = GetLastCommittedEntry()->Clone();
+
+  NavigationEntryImpl* new_entry = nullptr;
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kSitePerProcess)) {
+    // Make sure new_entry takes ownership of frame_entry in a scoped_refptr.
+    FrameNavigationEntry* frame_entry = new FrameNavigationEntry(
+        rfh->frame_tree_node()->frame_tree_node_id(), rfh->GetSiteInstance(),
+        params.url, params.referrer);
+    new_entry = GetLastCommittedEntry()->CloneAndReplace(rfh->frame_tree_node(),
+                                                         frame_entry);
+    CHECK(frame_entry->HasOneRef());
+  } else {
+    new_entry = GetLastCommittedEntry()->Clone();
+  }
+
   new_entry->SetPageID(params.page_id);
   InsertOrReplaceEntry(new_entry, false);
 }