Adds filter support for offscreen canvas

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

Index: third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
index 96b08881b9914554e5263eda267f112f451c59c1..80e4a1ca9595e5b7d5223d8689c61ccba0d0aee6 100644
--- a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
@@ -176,16 +176,18 @@ void OffscreenCanvasRenderingContext2D::didDraw(const SkIRect& dirtyRect)
 
 bool OffscreenCanvasRenderingContext2D::stateHasFilter()
 {
-    // TODO: crbug.com/593838 make hasFilter accept nullptr
-    // return state().hasFilter(nullptr, nullptr, IntSize(width(), height()), this);
-    return false;
+    return state().hasFilter(nullptr, getOffscreenCanvas()->size(), nullptr);
 }
 
 SkImageFilter* OffscreenCanvasRenderingContext2D::stateGetFilter()
 {
-    // TODO: make getFilter accept nullptr
-    // return state().getFilter(nullptr, nullptr, IntSize(width(), height()), this);
-    return nullptr;
+    SkImageFilter* f = state().getFilter(nullptr, getOffscreenCanvas()->size(), nullptr);
+    return f;
+}
+
+void OffscreenCanvasRenderingContext2D::setFilter(const String& filterString)
+{
+    BaseRenderingContext2D::setFilter(filterString);
 }
 
 void OffscreenCanvasRenderingContext2D::validateStateStack()