[WIP] Supporting arm_neon_optional flag for blink platform.

Source/platform/graphics/gpu/WebGLImageConversion.h

Index: Source/platform/graphics/gpu/WebGLImageConversion.h
diff --git a/Source/platform/graphics/gpu/WebGLImageConversion.h b/Source/platform/graphics/gpu/WebGLImageConversion.h
index 7a42a6077352759a60f92b779b4daa037d702fb9..2e5bf5c29b83972bb61fcfa2594ee4dc4ced30b3 100644
--- a/Source/platform/graphics/gpu/WebGLImageConversion.h
+++ b/Source/platform/graphics/gpu/WebGLImageConversion.h
@@ -163,6 +163,20 @@ private:
     static bool packPixels(const uint8_t* sourceData, DataFormat sourceDataFormat, unsigned width, unsigned height, unsigned sourceUnpackAlignment, unsigned destinationFormat, unsigned destinationType, AlphaOp, void* destinationData, bool flipY);
 };
 
+namespace SIMD {
+// None neon functions nothing do.
+ALWAYS_INLINE void unpackOneRowOfARGB16LittleToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfBGRA16LittleToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfRGB16LittleToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfRGB565ToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfRGBA16LittleToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfRGBA4444ToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void unpackOneRowOfRGBA5551ToRGBA8(const uint16_t*& source, uint8_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void packOneRowOfRGBA8ToUnsignedShort4444(const uint8_t*& source, uint16_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void packOneRowOfRGBA8ToUnsignedShort5551(const uint8_t*& source, uint16_t*& destination, unsigned& pixelsPerRow) { }
+ALWAYS_INLINE void packOneRowOfRGBA8ToUnsignedShort565(const uint8_t*& source, uint16_t*& destination, unsigned& pixelsPerRow) { }
+} // namespace SIMD
+
 } // namespace blink
 
 #endif // WebGLImageConversion_h