Clean up NativeTheme (particularly CommonTheme).

ui/native_theme/native_theme_dark_aura.cc

Index: ui/native_theme/native_theme_dark_aura.cc
diff --git a/ui/native_theme/native_theme_dark_aura.cc b/ui/native_theme/native_theme_dark_aura.cc
index 4683a65be010eb8a37e15ca7b9dbbe451e2659c9..d0d92739e5e7bd06a00192d907e16c64d116fb9b 100644
--- a/ui/native_theme/native_theme_dark_aura.cc
+++ b/ui/native_theme/native_theme_dark_aura.cc
@@ -4,7 +4,6 @@
 
 #include "ui/native_theme/native_theme_dark_aura.h"
 
-#include "ui/base/material_design/material_design_controller.h"
 #include "ui/gfx/color_palette.h"
 
 namespace ui {
@@ -15,11 +14,7 @@ NativeThemeDarkAura* NativeThemeDarkAura::instance() {
 }
 
 SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
-  if (!ui::MaterialDesignController::IsModeMaterial())
-    return NativeThemeAura::GetSystemColor(color_id);
-
   static const SkColor kPrimaryTextColor = SK_ColorWHITE;
-  static const SkColor kDefaultDarkBackground = SkColorSetRGB(0x3C, 0x3C, 0x3E);
 
   static const SkColor kButtonEnabledColor = SK_ColorWHITE;
 
@@ -45,8 +40,6 @@ SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
     // Label
     case kColorId_LabelEnabledColor:
       return kPrimaryTextColor;
-    case kColorId_LabelBackgroundColor:
-      return kDefaultDarkBackground;
 
     // Link
     case kColorId_LinkEnabled:
@@ -102,11 +95,8 @@ SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
     case kColorId_DialogBackground:
     case kColorId_BubbleBackground:
     case kColorId_UnfocusedBorderColor:
-    case kColorId_ButtonBackgroundColor:
     case kColorId_ButtonDisabledColor:
-    case kColorId_ButtonHighlightColor:
     case kColorId_ButtonHoverColor:
-    case kColorId_ButtonHoverBackgroundColor:
     case kColorId_BlueButtonEnabledColor:
     case kColorId_BlueButtonDisabledColor:
     case kColorId_BlueButtonPressedColor:
@@ -114,10 +104,8 @@ SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
     case kColorId_BlueButtonShadowColor:
     case kColorId_EnabledMenuItemForegroundColor:
     case kColorId_DisabledMenuItemForegroundColor:
-    case kColorId_DisabledEmphasizedMenuItemForegroundColor:
     case kColorId_SelectedMenuItemForegroundColor:
     case kColorId_FocusedMenuItemBackgroundColor:
-    case kColorId_HoverMenuItemBackgroundColor:
     case kColorId_MenuSeparatorColor:
     case kColorId_MenuBackgroundColor:
     case kColorId_MenuBorderColor: