PlzNavigate: Show error pages when the navigation failed before commit

content/browser/frame_host/navigator_impl.h

Index: content/browser/frame_host/navigator_impl.h
diff --git a/content/browser/frame_host/navigator_impl.h b/content/browser/frame_host/navigator_impl.h
index debf309aba67d4d3918bab66bedd250f7993ac0a..301a758f4f14796358e8cebbbe4f81dd74194515 100644
--- a/content/browser/frame_host/navigator_impl.h
+++ b/content/browser/frame_host/navigator_impl.h
@@ -77,6 +77,9 @@ class CONTENT_EXPORT NavigatorImpl : public Navigator {
   void CommitNavigation(FrameTreeNode* frame_tree_node,
                         ResourceResponse* response,
                         scoped_ptr<StreamHandle> body) override;
+  void FailedNavigation(FrameTreeNode* frame_tree_node,
+                        bool has_stale_copy_in_cache,
+                        int error_code) override;
   void LogResourceRequestTime(base::TimeTicks timestamp,
                               const GURL& url) override;
   void LogBeforeUnloadTime(