Fix BaseRenderingContext2D create/put/get-ImageData() for color managed canvas

third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h

 // Copyright 2016 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 OffscreenCanvasRenderingContext2D_h
 #define OffscreenCanvasRenderingContext2D_h
 
 #include "core/html/canvas/CanvasContextCreationAttributes.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/html/canvas/CanvasRenderingContextFactory.h"
@@ skipping 91 matching lines @@
     CanvasRenderingContext::NeedsFinalizeFrame();
   }
 
  private:
   bool needs_matrix_clip_restore_ = false;
   std::unique_ptr<ImageBuffer> image_buffer_;
 
   bool IsPaintable() const final;
 
   RefPtr<StaticBitmapImage> TransferToStaticBitmapImage();
+
+  CanvasColorSpace ColorSpace() const override;
+  String ColorSpaceAsString() const override;
+  CanvasPixelFormat PixelFormat() const override;
 };
 
 DEFINE_TYPE_CASTS(OffscreenCanvasRenderingContext2D,
                   CanvasRenderingContext,
                   context,
                   context->Is2d() && context->offscreenCanvas(),
                   context.Is2d() && context.offscreenCanvas());
 
 }  // namespace blink
 
 #endif  // OffscreenCanvasRenderingContext2D_h