PlzNavigate: remove extraneous DidStartLoading IPC

content/browser/frame_host/frame_tree_node.cc

Index: content/browser/frame_host/frame_tree_node.cc
diff --git a/content/browser/frame_host/frame_tree_node.cc b/content/browser/frame_host/frame_tree_node.cc
index 409a2a84932d6b0330cadc30c3eaa7e9121a972a..e94c5d8160c04b1e869fe40d9bcc0f39aaa84a8a 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -235,6 +235,11 @@ bool FrameTreeNode::IsLoading() const {
           switches::kEnableBrowserSideNavigation)) {
     if (navigation_request_)
       return true;
+
+    RenderFrameHostImpl* speculative_frame_host =
+        render_manager_.speculative_frame_host();
+    if (speculative_frame_host && speculative_frame_host->is_loading())
+      return true;
   } else {
     if (pending_frame_host && pending_frame_host->is_loading())
       return true;