Support subpixel values for text-shadow and box-shadow

Source/platform/animation/AnimationUtilities.h

Index: Source/platform/animation/AnimationUtilities.h
diff --git a/Source/platform/animation/AnimationUtilities.h b/Source/platform/animation/AnimationUtilities.h
index 9b92bd0b864d9e1748896c326be2cc0d25b0a522..7992f40e6d57a57cd3630a00aa5e558940f140fa 100644
--- a/Source/platform/animation/AnimationUtilities.h
+++ b/Source/platform/animation/AnimationUtilities.h
@@ -29,6 +29,7 @@
 #include "platform/LayoutUnit.h"
 #include "platform/PlatformExport.h"
 #include "platform/geometry/IntPoint.h"
+#include "platform/geometry/LayoutPoint.h"
 #include "wtf/MathExtras.h"
 #include "wtf/TypeTraits.h"
 
@@ -67,6 +68,11 @@ inline IntPoint blend(const IntPoint& from, const IntPoint& to, double progress)
     return IntPoint(blend(from.x(), to.x(), progress), blend(from.y(), to.y(), progress));
 }
 
+inline LayoutPoint blend(const LayoutPoint& from, const LayoutPoint& to, double progress)
+{
+    return LayoutPoint(blend(from.x(), to.x(), progress), blend(from.y(), to.y(), progress));
+}
+
 // Calculates the accuracy for evaluating a timing function for an animation with the specified duration.
 inline double accuracyForDuration(double duration)
 {