[SVG2] Add getters and setters to SVG*List interfaces.

Source/core/svg/SVGFEConvolveMatrixElement.cpp

Index: Source/core/svg/SVGFEConvolveMatrixElement.cpp
diff --git a/Source/core/svg/SVGFEConvolveMatrixElement.cpp b/Source/core/svg/SVGFEConvolveMatrixElement.cpp
index 113ee2d6b1b5183f831d4ddacc27b8c65bb260a5..ff626f20c85df2da2b0730f9f5658bc60b717f7f 100644
--- a/Source/core/svg/SVGFEConvolveMatrixElement.cpp
+++ b/Source/core/svg/SVGFEConvolveMatrixElement.cpp
@@ -203,7 +203,7 @@ PassRefPtr<FilterEffect> SVGFEConvolveMatrixElement::build(SVGFilterBuilder* fil
     if (orderXValue < 1 || orderYValue < 1)
         return nullptr;
     RefPtr<SVGNumberList> kernelMatrix = this->m_kernelMatrix->currentValue();
-    size_t kernelMatrixSize = kernelMatrix->numberOfItems();
+    size_t kernelMatrixSize = kernelMatrix->length();
     // The spec says this is a requirement, and should bail out if fails
     if (orderXValue * orderYValue != static_cast<int>(kernelMatrixSize))
         return nullptr;