Drop some dead code from FilterEffect

Source/platform/graphics/filters/FEComposite.h

Index: Source/platform/graphics/filters/FEComposite.h
diff --git a/Source/platform/graphics/filters/FEComposite.h b/Source/platform/graphics/filters/FEComposite.h
index 485f30298bcf9d322e703fcd0eae44aa9ff48952..7a622e279976f4bb63414bbf3d431284e6cb2e94 100644
--- a/Source/platform/graphics/filters/FEComposite.h
+++ b/Source/platform/graphics/filters/FEComposite.h
@@ -25,7 +25,6 @@
 
 #include "SkXfermode.h"
 #include "platform/graphics/filters/FilterEffect.h"
-#include "wtf/text/WTFString.h"
 
 namespace blink {
 
@@ -74,12 +73,6 @@ private:
 
     PassRefPtr<SkImageFilter> createImageFilterInternal(SkiaImageFilterBuilder*, bool requiresPMColorValidation);
 
-    template <int b1, int b4>
-    static inline void computeArithmeticPixelsNeon(unsigned char* source, unsigned  char* destination,
-        unsigned pixelArrayLength, float k1, float k2, float k3, float k4);
-    static inline void platformArithmeticNeon(unsigned char* source, unsigned  char* destination,
-        unsigned pixelArrayLength, float k1, float k2, float k3, float k4);
-
     CompositeOperationType m_type;
     float m_k1;
     float m_k2;