[Ash] Remove pre-MD code paths from HoverHighlightView

ash/common/system/tray/label_tray_view.cc

Index: ash/common/system/tray/label_tray_view.cc
diff --git a/ash/common/system/tray/label_tray_view.cc b/ash/common/system/tray/label_tray_view.cc
index 0c9e4dcdf87dc09be40ae893940e21ccfc36df46..e1c6156fb3758497a9ef16b0aec85f874ad50ff5 100644
--- a/ash/common/system/tray/label_tray_view.cc
+++ b/ash/common/system/tray/label_tray_view.cc
@@ -44,8 +44,7 @@ views::View* LabelTrayView::CreateChildView(
     const base::string16& message) const {
   HoverHighlightView* child = new HoverHighlightView(click_listener_);
   gfx::ImageSkia icon_image = gfx::CreateVectorIcon(icon_, kMenuIconColor);
-  child->AddIconAndLabelForDefaultView(icon_image, message,
-                                       false /* highlight */);
+  child->AddIconAndLabelForDefaultView(icon_image, message);
   child->text_label()->SetMultiLine(true);
   child->text_label()->SetAllowCharacterBreak(true);
   child->SetExpandable(true);