MainFrameObserver is inline owned, so it shouldn't be freed by OnDestruct

content/renderer/web_ui_mojo.h

Index: content/renderer/web_ui_mojo.h
diff --git a/content/renderer/web_ui_mojo.h b/content/renderer/web_ui_mojo.h
index f7179ef5d816447e1f314b56cdb14966d7e5fe53..769722ece0170b9e89081e4f16b54728ed37bdd9 100644
--- a/content/renderer/web_ui_mojo.h
+++ b/content/renderer/web_ui_mojo.h
@@ -40,6 +40,11 @@ class WebUIMojo
     void WillReleaseScriptContext(v8::Local<v8::Context> context,
                                   int world_id) override;
     void DidFinishDocumentLoad() override;
+    // MainFrameObserver is inline owned by WebUIMojo and should not be
+    // destroyed when the main RenderFrame is deleted. Overriding the
+    // OnDestruct method allows this object to remain alive and be cleaned
+    // up as part of WebUIMojo deletion.
+    void OnDestruct() override;
 
    private:
     WebUIMojo* web_ui_mojo_;