Introduce BubbleDialogDelegateView, which extends DialogDelegateView

ui/views/window/dialog_delegate.cc

Index: ui/views/window/dialog_delegate.cc
diff --git a/ui/views/window/dialog_delegate.cc b/ui/views/window/dialog_delegate.cc
index e6b179e538ae26e2f385864063a042d7d8560324..cb664d255967aeceb0e91e575adbef821592cdfb 100644
--- a/ui/views/window/dialog_delegate.cc
+++ b/ui/views/window/dialog_delegate.cc
@@ -98,7 +98,7 @@ View* DialogDelegate::CreateTitlebarExtraView() {
   return NULL;
 }
 
-View* DialogDelegate::CreateFootnoteView() {
+scoped_ptr<View> DialogDelegate::CreateFootnoteView() {
   return NULL;
 }
 
@@ -209,6 +209,7 @@ NonClientFrameView* DialogDelegate::CreateDialogFrameView(Widget* widget) {
   if (delegate) {
     frame->SetTitlebarExtraView(
         make_scoped_ptr(delegate->CreateTitlebarExtraView()));
+    frame->SetFootnoteView(delegate->CreateFootnoteView());
   }
   return frame;
 }