Allow nested state restorers in DrawingBuffer

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 252 matching lines @@
     void setPixelPackAlignmentDirty() { m_pixelPackAlignmentDirty = true; }
     void setTextureBindingDirty() { m_textureBindingDirty = true; }
     void setRenderbufferBindingDirty() { m_renderbufferBindingDirty = true; }
     void setFramebufferBindingDirty() { m_framebufferBindingDirty = true; }
     void setPixelUnpackBufferBindingDirty() {
       m_pixelUnpackBufferBindingDirty = true;
     }
 
    private:
     RefPtr<DrawingBuffer> m_drawingBuffer;
+    // The previous state restorer, in case restorers are nested.
+    ScopedStateRestorer* m_previousStateRestorer = nullptr;
     bool m_clearStateDirty = false;
     bool m_pixelPackAlignmentDirty = false;
     bool m_textureBindingDirty = false;
     bool m_renderbufferBindingDirty = false;
     bool m_framebufferBindingDirty = false;
     bool m_pixelUnpackBufferBindingDirty = false;
   };
 
   // All parameters necessary to generate the texture for the ColorBuffer.
   struct ColorBufferParameters {
@@ skipping 228 matching lines @@
   // RuntimeEnabledFeatures::webGLImageChromiumEnabled() call with
   // shouldUseChromiumImage() calls, and set m_chromiumImageUsage to
   // DisallowChromiumImage in the case of OffscreenCanvas.
   ChromiumImageUsage m_chromiumImageUsage;
   bool shouldUseChromiumImage();
 };
 
 }  // namespace blink
 
 #endif  // DrawingBuffer_h