Compute snap offsets (both repeat and element based)

third_party/WebKit/Source/platform/LengthFunctions.cpp

Index: third_party/WebKit/Source/platform/LengthFunctions.cpp
diff --git a/third_party/WebKit/Source/platform/LengthFunctions.cpp b/third_party/WebKit/Source/platform/LengthFunctions.cpp
index 7b19efefbe2e5537e4d5912f13c03a6c172dfda1..c5fd04177ab78aa6a537bb08985d9ebe4c35c023 100644
--- a/third_party/WebKit/Source/platform/LengthFunctions.cpp
+++ b/third_party/WebKit/Source/platform/LengthFunctions.cpp
@@ -25,6 +25,7 @@
 #include "platform/LengthFunctions.h"
 
 #include "platform/LayoutUnit.h"
+#include "platform/LengthPoint.h"
 #include "platform/LengthSize.h"
 
 namespace blink {
@@ -123,4 +124,9 @@ FloatSize floatSizeForLengthSize(const LengthSize& lengthSize, const FloatSize&
     return FloatSize(floatValueForLength(lengthSize.width(), boxSize.width()), floatValueForLength(lengthSize.height(), boxSize.height()));
 }
 
+FloatPoint floatPointForLengthPoint(const LengthPoint& LengthPoint, const FloatSize& boxSize)
+{
+    return FloatPoint(floatValueForLength(LengthPoint.x(), boxSize.width()), floatValueForLength(LengthPoint.y(), boxSize.height()));
+}
+
 } // namespace blink