Revert of Add new HTTP/2 and HPACK decoder in net/http2/. (patchset #19 id:400001 of https://codereview.chromium.org/2293613002/ )

Reason for revert:
Causing failures in net_unittests DecodeBufferDeathTest.NonNullBufferRequired on Mac (and maybe more).

Original issue's description:
> Add new HTTP/2 and HPACK decoder in net/http2/.
>
> A follow-up CL will add flags and new classes to net/spdy
> that will benefit from this new implementation.
>
> This CL lands all server changes in the http2 directory
> up to 129999723 by jamessynge.
>
> BUG=488484
>
> Committed: https://crrev.com/167743e8a7af542f317afde21d4ba19adc5b1f8f
> Cr-Commit-Position: refs/heads/master@{#436466}

TBR=jamessynge@chromium.org,rch@chromium.org,bnc@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=488484

Review-Url: https://codereview.chromium.org/2554683003
Cr-Commit-Position: refs/heads/master@{#436483}
126 files changed