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 3bfa207a8a034fa6d7e3630c66d0d057035917ee..478258817b9bfc97a8e70fa1f09f7a67cd795161 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);
@@ -76,6 +76,7 @@ class MODULES_EXPORT OffscreenCanvasRenderingContext2D final
   bool stateHasFilter() final;
   sk_sp<SkImageFilter> stateGetFilter() final;
   void snapshotStateForFilter() final {}
+  void setFilter(const String&);
 
   void validateStateStack() const final;