Prevent stack overflow in the serializer/deserializer.

Prevent stack overflow in the serializer/deserializer.

We keep an eye on the recursion depth. Once it exceeds a limit, we serialize
only the object header and size, but defer serializing the object body for
after we have unwound the stack.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1125073004

Cr-Commit-Position: refs/heads/master@{#28385}