Define accelerated steps time function.

webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc

Index: webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc
diff --git a/webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc b/webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc
index 6663267011a4e32d77fce8ced474e138176ac7da..75fd2d91328472c3f38998c9475e29e5dd0313c5 100644
--- a/webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc
+++ b/webkit/renderer/compositor_bindings/web_filter_animation_curve_impl.cc
@@ -34,6 +34,19 @@ void WebFilterAnimationCurveImpl::add(const WebFilterKeyframe& keyframe,
 }
 
 void WebFilterAnimationCurveImpl::add(const WebFilterKeyframe& keyframe,
+                                      int steps,
+                                      bool stepsAtStart) {
+  const cc::FilterOperations& filter_operations =
+      static_cast<const webkit::WebFilterOperationsImpl&>(keyframe.value())
+      .AsFilterOperations();
+      curve_->AddKeyframe(cc::FilterKeyframe::Create(
+          keyframe.time(),
+          filter_operations,
+          cc::StepsTimingFunction::Create(steps, stepsAtStart)
+            .PassAs<cc::TimingFunction>()));
+}
+
+void WebFilterAnimationCurveImpl::add(const WebFilterKeyframe& keyframe,
                                       double x1,
                                       double y1,
                                       double x2,