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

Source/platform/graphics/Color.cpp

Index: Source/platform/graphics/Color.cpp
diff --git a/Source/platform/graphics/Color.cpp b/Source/platform/graphics/Color.cpp
index 938e12cced410985b6be9c820ac5fb701b47fa33..92b0d44a612f4e8c560b39abab45928208fc3355 100644
--- a/Source/platform/graphics/Color.cpp
+++ b/Source/platform/graphics/Color.cpp
@@ -26,6 +26,7 @@
 #include "config.h"
 #include "platform/graphics/Color.h"
 
+#include "platform/graphics/ColorSpace.h"
 #include "wtf/Assertions.h"
 #include "wtf/DecimalNumber.h"
 #include "wtf/HexNumber.h"
@@ -332,6 +333,12 @@ Color Color::combineWithAlpha(float otherAlpha) const
     return colorWithOverrideAlpha(rgb(), (alpha() / 255.f) * otherAlpha);
 }
 
+Color Color::convertToLinear() const
+{
+    const Vector<uint8_t>& lookUpTable = getLinearRgbLUT();
+    return Color(lookUpTable[red()], lookUpTable[green()], lookUpTable[blue()], alpha());
+}
+
 static int blendComponent(int c, int a)
 {
     // We use white.