Allow Length::nonNanCalculatedValue to take a LayoutUnit

Source/platform/Length.cpp

Index: Source/platform/Length.cpp
diff --git a/Source/platform/Length.cpp b/Source/platform/Length.cpp
index 394a1c96e582fae509b23754d6469bc617b2de85..50b539d9df913f89f45b1b2f10b2ebbed0acb5b5 100644
--- a/Source/platform/Length.cpp
+++ b/Source/platform/Length.cpp
@@ -232,7 +232,7 @@ void Length::decrementCalculatedRef() const
     calcHandles().decrementRef(calculationHandle());
 }
 
-float Length::nonNanCalculatedValue(int maxValue) const
+float Length::nonNanCalculatedValue(float maxValue) const
 {
     ASSERT(isCalculated());
     float result = calculationValue().evaluate(maxValue);