[WIP] Supporting arm_neon_optional flag for blink platform.

Source/platform/graphics/filters/FEComposite.cpp

Index: Source/platform/graphics/filters/FEComposite.cpp
diff --git a/Source/platform/graphics/filters/FEComposite.cpp b/Source/platform/graphics/filters/FEComposite.cpp
index de333026e83e25fc0b638e8645799330846226dd..0f395053b71011fc95d1a09b8537a73fe52697c1 100644
--- a/Source/platform/graphics/filters/FEComposite.cpp
+++ b/Source/platform/graphics/filters/FEComposite.cpp
@@ -30,7 +30,9 @@
 #include "SkXfermodeImageFilter.h"
 
 #include "platform/graphics/GraphicsContext.h"
+#if HAVE(ARM_NEON_INTRINSICS)
 #include "platform/graphics/cpu/arm/filters/FECompositeArithmeticNEON.h"
+#endif
 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
 #include "platform/text/TextStream.h"
 #include "third_party/skia/include/core/SkDevice.h"
@@ -223,12 +225,7 @@ inline void FEComposite::platformArithmeticSoftware(Uint8ClampedArray* source, U
     int length = source->length();
     ASSERT(length == static_cast<int>(destination->length()));
     // The selection here eventually should happen dynamically.
-#if HAVE(ARM_NEON_INTRINSICS)
-    ASSERT(!(length & 0x3));
-    platformArithmeticNeon(source->data(), destination->data(), length, k1, k2, k3, k4);
-#else
-    arithmeticSoftware(source->data(), destination->data(), length, k1, k2, k3, k4);
-#endif
+    WTF_CPU_ARM_NEON_WRAP(arithmeticSoftware)(source->data(), destination->data(), length, k1, k2, k3, k4);
 }
 
 FloatRect FEComposite::determineAbsolutePaintRect(const FloatRect& originalRequestedRect)