Make OffscreenCanvasRenderingContext2D renderable on a worker

third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.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 BaseRenderingContext2D_h
 #define BaseRenderingContext2D_h
 
 #include "bindings/core/v8/UnionTypesCore.h"
 #include "bindings/modules/v8/UnionTypesModules.h"
 #include "modules/ModulesExport.h"
 #include "modules/canvas2d/CanvasGradient.h"
 #include "modules/canvas2d/CanvasPathMethods.h"
 #include "modules/canvas2d/CanvasRenderingContext2DState.h"
 #include "modules/canvas2d/CanvasStyle.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace blink {
 
 class CanvasImageSource;
 class Color;
+class FilterOperations;
 class Image;
 class ImageBuffer;
 class Path2D;
 class SVGMatrixTearOff;
 
 typedef HTMLImageElementOrHTMLVideoElementOrHTMLCanvasElementOrImageBitmap CanvasImageSourceUnion;
 
 class MODULES_EXPORT BaseRenderingContext2D : public WillBeGarbageCollectedMixin, public CanvasPathMethods {
     WTF_MAKE_NONCOPYABLE(BaseRenderingContext2D);
 public:
@@ skipping 117 matching lines @@
 
     virtual bool stateHasFilter() = 0;
     virtual SkImageFilter* stateGetFilter() = 0;
 
     virtual void validateStateStack() = 0;
 
     virtual bool hasAlpha() const = 0;
 
     virtual bool isContextLost() const = 0;
 
+    virtual void updateFilterReferences(const FilterOperations& filters) { }

[Stephen White, 2016/03/08 22:46:32]

Could these filter-related changes be made in another patch?

+
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     BaseRenderingContext2D();
 
     CanvasRenderingContext2DState& modifiableState();
     const CanvasRenderingContext2DState& state() const { return *m_stateStack.last(); }
 
     bool computeDirtyRect(const FloatRect& localBounds, SkIRect*);
     bool computeDirtyRect(const FloatRect& localBounds, const SkIRect& transformedClipBounds, SkIRect*);
@@ skipping 114 matching lines @@
     foregroundPaint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     c->setMatrix(ctm);
     drawFunc(c, &foregroundPaint);
     c->restore();
     c->setMatrix(ctm);
 }
 
 } // namespace blink
 
 #endif // BaseRenderingContext2D_h