Revert of Remove some pre-md code and assets.

ash/common/system/chromeos/brightness/tray_brightness.cc

Index: ash/common/system/chromeos/brightness/tray_brightness.cc
diff --git a/ash/common/system/chromeos/brightness/tray_brightness.cc b/ash/common/system/chromeos/brightness/tray_brightness.cc
index b526202197cc6f6bbedc48841949ba5004a90137..0240a979debf6645840cff5a79dcc86d00b75db8 100644
--- a/ash/common/system/chromeos/brightness/tray_brightness.cc
+++ b/ash/common/system/chromeos/brightness/tray_brightness.cc
@@ -6,6 +6,7 @@
 
 #include <algorithm>
 
+#include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/system/brightness_control_delegate.h"
 #include "ash/common/system/tray/tray_constants.h"
@@ -102,8 +103,13 @@
 
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   views::ImageView* icon = TrayPopupUtils::CreateMainImageView();
-  icon->SetImage(
-      gfx::CreateVectorIcon(kSystemMenuBrightnessIcon, kMenuIconColor));
+  if (MaterialDesignController::IsSystemTrayMenuMaterial()) {
+    icon->SetImage(
+        gfx::CreateVectorIcon(kSystemMenuBrightnessIcon, kMenuIconColor));
+  } else {
+    icon->SetImage(
+        rb.GetImageNamed(IDR_AURA_UBER_TRAY_BRIGHTNESS).ToImageSkia());
+  }
   tri_view->AddView(TriView::Container::START, icon);
 
   slider_ = TrayPopupUtils::CreateSlider(this);