Adds filter support for offscreen canvas

third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp

Index: third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp
diff --git a/third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp b/third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp
index 7c862d840f9cd9fdde9d701dbab94b12405627fe..8147307f0047b57292aa8fe0be0d09c72e2693cf 100644
--- a/third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp
+++ b/third_party/WebKit/Source/core/paint/FilterEffectBuilder.cpp
@@ -120,6 +120,14 @@ Vector<float> sepiaMatrix(double amount) {
 
 }  // namespace
 
+FilterEffectBuilder::FilterEffectBuilder(const FloatRect& zoomedReferenceBox,
+                                         float zoom,
+                                         const SkPaint* fillPaint,
+                                         const SkPaint* strokePaint) {
+  FilterEffectBuilder(nullptr, zoomedReferenceBox, zoom, fillPaint,
+                      strokePaint);
+}
+
 FilterEffectBuilder::FilterEffectBuilder(Node* target,
                                          const FloatRect& zoomedReferenceBox,
                                          float zoom,