Update WEBKIT_VERSION

Author: sosukesuzuki

cmake/tools/SetupWebKit.cmake

@@ -2,7 +2,7 @@ option(WEBKIT_VERSION "The version of WebKit to use")
 option(WEBKIT_LOCAL "If a local version of WebKit should be used instead of downloading")
 
 if(NOT WEBKIT_VERSION)
-  set(WEBKIT_VERSION preview-pr-124-ae95679d)
+  set(WEBKIT_VERSION preview-pr-124-4a684d45)
 endif()
 
 string(SUBSTRING ${WEBKIT_VERSION} 0 16 WEBKIT_VERSION_PREFIX)