bindings: preparation for fixing incorrect dependency of SerializedScriptValue.

Split Writer, Reader, Serializer and Deserializer off from SerializedScriptValue.cpp.

The goal is https://codereview.chromium.org/718383003/

BUG=358074

Review URL: https://codereview.chromium.org/721133002

git-svn-id: svn://svn.chromium.org/blink/trunk@185349 bbb929c8-8fbe-4397-9dbb-9b2b20218538