IDL compiler: Drop support of serializer in WebIDL

Serializer was deprecated in spec, and we no longer have it in other than test IDLs.
This CL drops support of it from our IDL compiler.

Change-Id: I7734e10f76283e387156f79f4e518dc158d0c265
Reviewed-by: Kentaro Hara <>
Reviewed-by: Yuki Shiino <>
Commit-Queue: Hitoshi Yoshida <>
Cr-Commit-Position: refs/heads/master@{#625165}
12 files changed