Add support for converting Colors to linear RGB; Fix relevant filters

Source/platform/graphics/filters/FilterEffect.cpp

Index: Source/platform/graphics/filters/FilterEffect.cpp
diff --git a/Source/platform/graphics/filters/FilterEffect.cpp b/Source/platform/graphics/filters/FilterEffect.cpp
index d70f534081386d14850d5947da68be05971ef046..c55c2532daa5cb8c38a02a10afcdb889d142d975 100644
--- a/Source/platform/graphics/filters/FilterEffect.cpp
+++ b/Source/platform/graphics/filters/FilterEffect.cpp
@@ -458,6 +458,13 @@ Uint8ClampedArray* FilterEffect::createPremultipliedImageResult()
     return m_premultipliedImageResult.get();
 }
 
+Color FilterEffect::adaptColorToOperatingColorSpace(const Color& deviceColor)
+{
+    if (operatingColorSpace() == ColorSpaceLinearRGB)
+        return deviceColor.convertToLinear();
+    return deviceColor;
+}
+
 void FilterEffect::transformResultColorSpace(ColorSpace dstColorSpace)
 {
     if (!hasResult() || dstColorSpace == m_resultColorSpace)