Refactor ImageBuffer to make OffscreenCanvas match HTMLCanvasElement

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

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  *
  * 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
@@ skipping 35 matching lines @@
                                      // of zero
   kIncompleteSourceImageStatus,  // Image element with no source media
   kInvalidSourceImageStatus,
 };
 
 class CORE_EXPORT CanvasImageSource {
  public:
   virtual PassRefPtr<Image> GetSourceImageForCanvas(SourceImageStatus*,
                                                     AccelerationHint,
                                                     SnapshotReason,
-                                                    const FloatSize&) const = 0;
+                                                    const FloatSize&) = 0;
 
   // IMPORTANT: Result must be independent of whether destinationContext is
   // already tainted because this function may be used to determine whether
   // a CanvasPattern is "origin clean", and that pattern may be used on
   // another canvas, which may not be already tainted.
   virtual bool WouldTaintOrigin(
       SecurityOrigin* destination_security_origin) const = 0;
 
   virtual bool IsCSSImageValue() const { return false; }
   virtual bool IsVideoElement() const { return false; }
@@ skipping 20 matching lines @@
   virtual int SourceWidth() = 0;
   virtual int SourceHeight() = 0;
 
  protected:
   virtual ~CanvasImageSource() {}
 };
 
 }  // namespace blink
 
 #endif