Allow dialogs to use a custom View as their title.

ui/views/bubble/bubble_dialog_delegate.cc

Index: ui/views/bubble/bubble_dialog_delegate.cc
diff --git a/ui/views/bubble/bubble_dialog_delegate.cc b/ui/views/bubble/bubble_dialog_delegate.cc
index b8be537b9912cb78562f726d0e441f52bab0c8e4..391d8cdb5ac154cf254192da65530541c5363c8c 100644
--- a/ui/views/bubble/bubble_dialog_delegate.cc
+++ b/ui/views/bubble/bubble_dialog_delegate.cc
@@ -158,6 +158,14 @@ void BubbleDialogDelegateView::OnWidgetBoundsChanged(
     SizeToContents();
 }
 
+void BubbleDialogDelegateView::AddedToWidget() {
+  View* title_view = CreateTitleView();
+  if (title_view) {
+    GetBubbleFrameView()->SetTitleView(title_view);
+    PropagateUpdateTitleView(title_view);
+  }
+}
+
 View* BubbleDialogDelegateView::GetAnchorView() const {
   return anchor_view_tracker_->view();
 }
@@ -241,6 +249,15 @@ const gfx::FontList& BubbleDialogDelegateView::GetTitleFontList() const {
   return rb.GetFontList(ui::ResourceBundle::MediumFont);
 }
 
+View* BubbleDialogDelegateView::CreateTitleView() {
+  return nullptr;
+}
+
+void BubbleDialogDelegateView::PropagateUpdateTitleView(View* title_view) {
+  if (title_view)
+    UpdateTitleView(title_view, GetWindowTitle(), ShouldShowWindowTitle());
+}
+
 void BubbleDialogDelegateView::OnNativeThemeChanged(
     const ui::NativeTheme* theme) {
   UpdateColorsFromTheme(theme);