[UI] Invalidate Layout in BubbleFrameView::SetHeaderView()

We need to invalidate the layout, in case the Header view is changed
after the bubble has been created.

This is also aligned with SetFootnoteView().

Bug: 1115936
Change-Id: I66896d7beeda5e2996ee9c72fad0bdbf99a268a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2421517
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809012}

ui/views/bubble/bubble_frame_view.cc

@@ -535,6 +535,8 @@ void BubbleFrameView::SetHeaderView(std::unique_ptr<View> view) {
 
   if (view)
     header_view_ = AddChildViewAt(std::move(view), 0);
+
+  InvalidateLayout();
 }
 
 void BubbleFrameView::SetFootnoteView(std::unique_ptr<View> view) {