Make MdTextButton a LabelButton, use it in the DL shelf.

chrome/browser/ui/views/download/download_item_view_md.cc

Index: chrome/browser/ui/views/download/download_item_view_md.cc
diff --git a/chrome/browser/ui/views/download/download_item_view_md.cc b/chrome/browser/ui/views/download/download_item_view_md.cc
index 359bf407307f3976e917904ff41e25f79b273417..98316798e7b836ade7fcab34ad3860208e277181 100644
--- a/chrome/browser/ui/views/download/download_item_view_md.cc
+++ b/chrome/browser/ui/views/download/download_item_view_md.cc
@@ -60,6 +60,7 @@
 #include "ui/views/border.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/button/label_button.h"
+#include "ui/views/controls/button/md_text_button.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/mouse_constants.h"
 #include "ui/views/widget/root_view.h"
@@ -891,14 +892,14 @@ void DownloadItemViewMd::ShowWarningDialog() {
 
   dropdown_state_ = NORMAL;
   if (mode_ == DANGEROUS_MODE) {
-    save_button_ =
-        new views::LabelButton(this, model_.GetWarningConfirmButtonText());
+    save_button_ = views::MdTextButton::CreateStandardButton(
+        this, model_.GetWarningConfirmButtonText());
     save_button_->SetStyle(views::Button::STYLE_BUTTON);
     AddChildView(save_button_);
   }
   int discard_button_message =
       model_.IsMalicious() ? IDS_DISMISS_DOWNLOAD : IDS_DISCARD_DOWNLOAD;
-  discard_button_ = new views::LabelButton(
+  discard_button_ = views::MdTextButton::CreateStandardButton(
       this, l10n_util::GetStringUTF16(discard_button_message));
   discard_button_->SetStyle(views::Button::STYLE_BUTTON);
   AddChildView(discard_button_);