Enable Ash material design shelf and system menu by default

ash/common/material_design/material_design_controller.cc

Index: ash/common/material_design/material_design_controller.cc
diff --git a/ash/common/material_design/material_design_controller.cc b/ash/common/material_design/material_design_controller.cc
index 918e3f82fe147bc00284ba1a40aab4a1ec5c54bc..b1db3e2a3239e72676ca568f87ad9cfe411e1979 100644
--- a/ash/common/material_design/material_design_controller.cc
+++ b/ash/common/material_design/material_design_controller.cc
@@ -50,7 +50,7 @@ MaterialDesignController::Mode MaterialDesignController::GetMode() {
 
 // static
 bool MaterialDesignController::IsShelfMaterial() {
-  return MaterialDesignController::IsMaterialExperimental();
+  return IsMaterial();
 }
 
 // static
@@ -60,12 +60,12 @@ bool MaterialDesignController::IsImmersiveModeMaterial() {
 
 // static
 bool MaterialDesignController::IsSystemTrayMenuMaterial() {
-  return MaterialDesignController::IsMaterialExperimental();
+  return IsMaterial();
 }
 
 // static
 bool MaterialDesignController::UseMaterialDesignSystemIcons() {
-  return MaterialDesignController::IsMaterialExperimental();
+  return IsMaterial();
 }
 
 // static