[Fetch] Remove Request.body.

This CL tentatively removes Request.body property in order not to complicate the
implementation. Request.body is not yet specified and the implementation is
currently broken in some ways.

R=hiroshige
BUG=435393

Review URL: https://codereview.chromium.org/1043133002

git-svn-id: svn://svn.chromium.org/blink/trunk@192829 bbb929c8-8fbe-4397-9dbb-9b2b20218538
5 files changed