Fix Harmony popover buttons being flush with their content.

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..502bc0b8a2a032fff9af4d84790b0b4f0dd3195e 100644
--- a/ui/views/bubble/bubble_dialog_delegate.cc
+++ b/ui/views/bubble/bubble_dialog_delegate.cc
@@ -98,7 +98,11 @@ bool BubbleDialogDelegateView::ShouldShowCloseButton() const {
 
 ClientView* BubbleDialogDelegateView::CreateClientView(Widget* widget) {
   DialogClientView* client = new DialogClientView(widget, GetContentsView());
-  client->SetButtonRowInsets(gfx::Insets());
+  LayoutProvider* provider = LayoutProvider::Get();
+  // The other three sides are taken care of by the |margins_| given to
+  // BubbleFrameView in CreateNonClientFrameView().
+  client->SetButtonRowInsets(gfx::Insets(
+      provider->GetDistanceMetric(DISTANCE_BUBBLE_BUTTON_TOP_MARGIN), 0, 0, 0));
   widget->non_client_view()->set_mirror_client_in_rtl(mirror_arrow_in_rtl_);
   return client;
 }