Minor clean up in transferToImageBitmap API

third_party/WebKit/Source/core/html/canvas/CanvasRenderingContext.h

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 144 matching lines @@
   virtual int externallyAllocatedBytesPerPixel() {
     NOTREACHED();
     return 0;
   }
 
   // ImageBitmap-specific interface
   virtual bool paint(GraphicsContext&, const IntRect&) { return false; }
 
   // OffscreenCanvas-specific methods
   OffscreenCanvas* getOffscreenCanvas() const { return m_offscreenCanvas; }
-  virtual ImageBitmap* transferToImageBitmap(ExceptionState&) {
-    return nullptr;
-  }
+  virtual ImageBitmap* transferToImageBitmap() { return nullptr; }
 
   bool wouldTaintOrigin(CanvasImageSource*, SecurityOrigin* = nullptr);
   void didMoveToNewDocument(Document*);
 
   void detachCanvas() { m_canvas = nullptr; }
 
   const CanvasContextCreationAttributes& creationAttributes() const {
     return m_creationAttributes;
   }
 
@@ skipping 11 matching lines @@
   Member<OffscreenCanvas> m_offscreenCanvas;
   HashSet<String> m_cleanURLs;
   HashSet<String> m_dirtyURLs;
   CanvasColorSpace m_colorSpace;
   CanvasContextCreationAttributes m_creationAttributes;
 };
 
 }  // namespace blink
 
 #endif