Remove a bunch of NPAPI quirks and related support code

content/browser/renderer_host/render_widget_host_view_mus.h

 // Copyright 2015 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 CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MUS_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MUS_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 106 matching lines @@
   bool PostProcessEventForPluginIme(
       const NativeWebKeyboardEvent& event) override;
 #endif  // defined(OS_MACOSX)
 
   void LockCompositingSurface() override;
   void UnlockCompositingSurface() override;
 
 #if defined(OS_WIN)
   void SetParentNativeViewAccessible(
       gfx::NativeViewAccessible accessible_parent) override;
-  gfx::NativeViewId GetParentForWindowlessPlugin() const override;
 #endif
 
   RenderWidgetHostImpl* host_;
 
   aura::Window* aura_window_;
 
   scoped_ptr<mus::ScopedWindowPtr> mus_window_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMus);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MUS_H_