Gut ash::MaterialDesignController, and remove the about:flags entry.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 0cbbdd09e2daec2d613451a97828798195988c8a..c4a108d47a6c3a843a2f79ca77c2dca73991fc10 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -186,7 +186,6 @@
 #endif  // defined(OS_LINUX) && !defined(OS_CHROMEOS)
 
 #if defined(OS_CHROMEOS)
-#include "ash/common/material_design/material_design_controller.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/settings/cros_settings_names.h"
@@ -1055,9 +1054,6 @@ int ChromeBrowserMainParts::PreCreateThreadsImpl() {
   // are not available until this point. Now that they are, proceed with
   // initializing the MaterialDesignController.
   ui::MaterialDesignController::Initialize();
-#if defined(OS_CHROMEOS)
-  ash::MaterialDesignController::Initialize();
-#endif  // !defined(OS_CHROMEOS)
 
 #if defined(OS_WIN)
   // This is needed to enable ETW exporting when requested in about:flags.