Revert of Remove enable_topchrome_md build flag

ui/base/material_design/material_design_controller.cc

Index: ui/base/material_design/material_design_controller.cc
diff --git a/ui/base/material_design/material_design_controller.cc b/ui/base/material_design/material_design_controller.cc
index 6718a185e2fb04523a001e2c5a6b6e2cf89e2219..86685cf5114f2d0db70683e5828e42960227dfe2 100644
--- a/ui/base/material_design/material_design_controller.cc
+++ b/ui/base/material_design/material_design_controller.cc
@@ -37,6 +37,9 @@
 void MaterialDesignController::Initialize() {
   TRACE_EVENT0("startup", "MaterialDesignController::InitializeMode");
   CHECK(!is_mode_initialized_);
+#if !defined(ENABLE_TOPCHROME_MD)
+  SetMode(NON_MATERIAL);
+#else
   const std::string switch_value =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kTopChromeMD);
@@ -58,6 +61,7 @@
 
   include_secondary_ui_ = base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kExtendMdToSecondaryUi);
+#endif  // !defined(ENABLE_TOPCHROME_MD)
 }
 
 // static