--- a/chrome/browser/ui/tabs/tab_strip_model_observer.h
+++ b/chrome/browser/ui/tabs/tab_strip_model_observer.h
@@ -135,7 +135,7 @@ class TabStripModelChange {

  private:
   const Type type_ = kSelectionOnly;
-  const std::vector<Delta> deltas_;
+  std::vector<Delta> deltas_;

   DISALLOW_COPY_AND_ASSIGN(TabStripModelChange);
 };