[WIP] Supporting arm_neon_optional flag for blink platform.

Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h

Index: Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h
diff --git a/Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h b/Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h
index 3cd842879b088c56403824ca0b9e782c50ae0421..c6e926355c8567284a28a395dd49405d5e4d901b 100644
--- a/Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h
+++ b/Source/platform/graphics/cpu/arm/filters/FEBlendNEON.h
@@ -166,6 +166,46 @@ void FEBlend::platformApplyNEON(unsigned char* srcPixelArrayA, unsigned char* sr
     }
 }
 
+void FEBlend::applySoftwareInternalNEON()
+{
+    if (m_mode != WebBlendModeNormal
+        && m_mode != WebBlendModeMultiply
+        && m_mode != WebBlendModeScreen
+        && m_mode != WebBlendModeDarken
+        && m_mode != WebBlendModeLighten)
+        return applySoftwareInternal();
+
+    Uint8ClampedArray* dstPixelArray = createPremultipliedImageResult();
+    if (!dstPixelArray)
+        return;
+
+    FilterEffect* in = inputEffect(0);
+    FilterEffect* in2 = inputEffect(1);
+
+    IntRect effectADrawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
+    RefPtr<Uint8ClampedArray> srcPixelArrayA = in->asPremultipliedImage(effectADrawingRect);
+
+    IntRect effectBDrawingRect = requestedRegionOfInputImageData(in2->absolutePaintRect());
+    RefPtr<Uint8ClampedArray> srcPixelArrayB = in2->asPremultipliedImage(effectBDrawingRect);
+
+    unsigned pixelArrayLength = srcPixelArrayA->length();
+    ASSERT(pixelArrayLength == srcPixelArrayB->length());
+
+    if (pixelArrayLength >= 8) {
+        platformApplyNEON(srcPixelArrayA->data(), srcPixelArrayB->data(), dstPixelArray->data(), pixelArrayLength);
+    } else {
+        // If there is just one pixel we expand it to two.
+        ASSERT(pixelArrayLength > 0);
+        uint32_t sourceA[2] = {0, 0};
+        uint32_t sourceBAndDest[2] = {0, 0};
+
+        sourceA[0] = reinterpret_cast<uint32_t*>(srcPixelArrayA->data())[0];
+        sourceBAndDest[0] = reinterpret_cast<uint32_t*>(srcPixelArrayB->data())[0];
+        platformApplyNEON(reinterpret_cast<uint8_t*>(sourceA), reinterpret_cast<uint8_t*>(sourceBAndDest), reinterpret_cast<uint8_t*>(sourceBAndDest), 8);
+        reinterpret_cast<uint32_t*>(dstPixelArray->data())[0] = sourceBAndDest[0];
+    }
+}
+
 } // namespace blink
 
 #endif // HAVE(ARM_NEON_INTRINSICS)