Fix FEConvolveMatrix bias issue.

Source/platform/graphics/filters/FEConvolveMatrix.cpp

Index: Source/platform/graphics/filters/FEConvolveMatrix.cpp
diff --git a/Source/platform/graphics/filters/FEConvolveMatrix.cpp b/Source/platform/graphics/filters/FEConvolveMatrix.cpp
index a96eaa1608f3cdd2188270bec2c72dc75112223a..ea854710995810b11f32ef35b9ac93f4565b31f2 100644
--- a/Source/platform/graphics/filters/FEConvolveMatrix.cpp
+++ b/Source/platform/graphics/filters/FEConvolveMatrix.cpp
@@ -527,7 +527,7 @@ PassRefPtr<SkImageFilter> FEConvolveMatrix::createImageFilter(SkiaImageFilterBui
     SkISize kernelSize(SkISize::Make(m_kernelSize.width(), m_kernelSize.height()));
     int numElements = kernelSize.width() * kernelSize.height();
     SkScalar gain = SkFloatToScalar(1.0f / m_divisor);
-    SkScalar bias = SkFloatToScalar(m_bias);
+    SkScalar bias = SkFloatToScalar(m_bias * 255);
     SkIPoint target = SkIPoint::Make(m_targetOffset.x(), m_targetOffset.y());
     SkMatrixConvolutionImageFilter::TileMode tileMode = toSkiaTileMode(m_edgeMode);
     bool convolveAlpha = !m_preserveAlpha;