Adds filter support for offscreen canvas

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

Index: third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h
diff --git a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h
index 481fe91633b005d6836b8d70113b836d8c08c2d9..63fb9bfee82e3093f17389b7000cec0c980a3ec8 100644
--- a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h
+++ b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h
@@ -44,8 +44,8 @@ class MODULES_EXPORT OffscreenCanvasRenderingContext2D final
   ContextType getContextType() const override { return Context2d; }
   bool is2d() const override { return true; }
   void setOffscreenCanvasGetContextResult(OffscreenRenderingContext&) final;
-  void setIsHidden(bool) final { ASSERT_NOT_REACHED(); }
-  void stop() final { ASSERT_NOT_REACHED(); }
+  void setIsHidden(bool) final { NOTREACHED(); }
+  void stop() final { NOTREACHED(); }
   void setCanvasGetContextResult(RenderingContext&) final {}
   void clearRect(double x, double y, double width, double height) override {
     BaseRenderingContext2D::clearRect(x, y, width, height);
@@ -75,6 +75,7 @@ class MODULES_EXPORT OffscreenCanvasRenderingContext2D final
   bool stateHasFilter() final;
   SkImageFilter* stateGetFilter() final;
   void snapshotStateForFilter() final {}
+  void setFilter(const String&);
 
   void validateStateStack() const final;