Removing canvas rendering mode switching feature

third_party/WebKit/Source/core/html/HTMLCanvasElement.h

 /*
  * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 317 matching lines @@
   bool image_buffer_is_clear_;
   std::unique_ptr<ImageBuffer> image_buffer_;
 
   // FIXME: This is temporary for platforms that have to copy the image buffer
   // to render (and for CSSCanvasValue).
   mutable RefPtr<Image> copied_image_;
 
   // Used for OffscreenCanvas that controls this HTML canvas element
   std::unique_ptr<CanvasSurfaceLayerBridge> surface_layer_bridge_;
 
-  int num_frames_since_last_rendering_mode_switch_;
-  bool pending_rendering_mode_switch_;
   bool did_notify_listeners_for_current_frame_ = false;
 };
 
 }  // namespace blink
 
 #endif  // HTMLCanvasElement_h