Remove a bunch of pre-MD toolbar code and assets.

chrome/browser/ui/cocoa/toolbar/app_toolbar_button.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_COCOA_TOOLBAR_APP_TOOLBAR_BUTTON_H_
 #define CHROME_BROWSER_UI_COCOA_TOOLBAR_APP_TOOLBAR_BUTTON_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include <memory>
 
 #import "chrome/browser/ui/cocoa/menu_button.h"
 #include "chrome/browser/ui/toolbar/app_menu_icon_controller.h"
-#include "chrome/browser/ui/toolbar/app_menu_icon_painter.h"
-
-class AppMenuButtonIconPainterDelegateMac;
 
 // Button for the app toolbar button.
 @interface AppToolbarButton : MenuButton {
  @private
-  std::unique_ptr<AppMenuButtonIconPainterDelegateMac> delegate_;
-  AppMenuIconPainter::Severity severity_;
+  AppMenuIconController::Severity severity_;
   AppMenuIconController::IconType type_;
 }
 
-- (void)setSeverity:(AppMenuIconPainter::Severity)severity
+- (void)setSeverity:(AppMenuIconController::Severity)severity
            iconType:(AppMenuIconController::IconType)iconType
       shouldAnimate:(BOOL)shouldAnimate;
 
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_TOOLBAR_APP_TOOLBAR_BUTTON_H_