Move some class-scope constants to file-scope in the lone subclass using them.

chrome/browser/ui/views/infobars/confirm_infobar.cc

Index: chrome/browser/ui/views/infobars/confirm_infobar.cc
diff --git a/chrome/browser/ui/views/infobars/confirm_infobar.cc b/chrome/browser/ui/views/infobars/confirm_infobar.cc
index 810bec2b4dd49a1bff17d3b4b50902c4738bbc3a..593af479621f65e4bd9e805ff9a044955cb8fb9b 100644
--- a/chrome/browser/ui/views/infobars/confirm_infobar.cc
+++ b/chrome/browser/ui/views/infobars/confirm_infobar.cc
@@ -18,6 +18,14 @@
 #include "ui/views/controls/button/md_text_button.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/link.h"
+#include "ui/views/layout/layout_constants.h"
+
+namespace {
+
+constexpr int kButtonButtonSpacing = views::kRelatedButtonHSpacing;
+constexpr int kEndOfLabelSpacing = views::kItemLabelSpacing;
+
+}  // namespace
 
 // InfoBarService -------------------------------------------------------------