[MD] Apply appropriate call to action styling to infobar buttons.

chrome/browser/ui/views/infobars/infobar_view.h

Index: chrome/browser/ui/views/infobars/infobar_view.h
diff --git a/chrome/browser/ui/views/infobars/infobar_view.h b/chrome/browser/ui/views/infobars/infobar_view.h
index 0aba01c1554f6e60b390d700fe157fc09276a1b1..d7e80b6ad3569e3d6bb3c82bebbd6e6874abfd81 100644
--- a/chrome/browser/ui/views/infobars/infobar_view.h
+++ b/chrome/browser/ui/views/infobars/infobar_view.h
@@ -26,6 +26,7 @@ class Label;
 class LabelButton;
 class Link;
 class LinkListener;
+class MdTextButton;
 class MenuButton;
 class MenuRunner;
 }  // namespace views
@@ -58,10 +59,14 @@ class InfoBarView : public infobars::InfoBar,
                           views::LinkListener* listener) const;
 
   // Creates a focusable button for use on an infobar. The appearance is
-  // customized for infobars (except in Material mode).
+  // customized for infobars. Used for pre-MD only.
   // NOTE: Subclasses must ignore button presses if we're unowned.
   static views::LabelButton* CreateTextButton(views::ButtonListener* listener,
                                               const base::string16& text);
+  // As above, but used for MD.
+  static views::MdTextButton* CreateMdTextButton(
+      views::ButtonListener* listener,
+      const base::string16& text);
 
   // Given |labels| and the total |available_width| to display them in, sets
   // each label's size so that the longest label shrinks until it reaches the