[WIP] Supporting arm_neon_optional flag for blink platform.

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 1073778b22422a4e31cab460c88283a5fe58b679..453e9dd5e97c1f0f2d1666a255f95e1407cd3007 100644
--- a/Source/platform/graphics/filters/FEComposite.h
+++ b/Source/platform/graphics/filters/FEComposite.h
@@ -78,11 +78,13 @@ private:
 
     inline void platformArithmeticSoftware(Uint8ClampedArray* source, Uint8ClampedArray* destination,
         float k1, float k2, float k3, float k4);
+#if HAVE(ARM_NEON_INTRINSICS)
     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);
+    static inline void arithmeticSoftwareNEON(unsigned char* source, unsigned  char* destination,
+        int pixelArrayLength, float k1, float k2, float k3, float k4);
+#endif
 
     CompositeOperationType m_type;
     float m_k1;