Revert of Net: Stop treating partial HTTP headers as a valid response.

Revert of Net:  Stop treating partial HTTP headers as a valid response. (patchset #7 id:160001 of https://codereview.chromium.org/1266713007/ )

Reason for revert:
Might broke http/tests/security/XFrameOptions/x-frame-options-cached.html
http/tests/security/contentSecurityPolicy/cached-frame-csp.html
http/tests/security/xssAuditor/cached-frame.html on windows blink bots

Original issue's description:
> Net:  Stop treating partial HTTP headers as a valid response.
>
> For now, we return ERR_RESPONSE_HEADERS_TRUNCATED in this case.  Longer
> term, we probably want to get rid of the extra code to detect when this
> happens.
>
> Also do a bit of cleanup in HttpStreamParser's error handling code.
>
> BUG=472762
>
> Committed: https://crrev.com/854d9c86cc897fdf55ea917d2aed2070e9235dac
> Cr-Commit-Position: refs/heads/master@{#341744}

TBR=davidben@chromium.org,thestig@chromium.org,jyasskin@chromium.org,mmenke@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=472762
Committed: https://crrev.com/9528c9f4b7200659c10da799aaface62c19af91b
Cr-Commit-Position: refs/heads/master@{#341809}

[Zhenyao Mo, 2015-08-04 22:07:46]

Created Revert of Net:  Stop treating partial HTTP headers as a valid response.

[commit-bot: I haz the power, 2015-08-04 22:08:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1255123006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1255123006/1

[commit-bot: I haz the power, 2015-08-04 22:12:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-04 22:17:31]

Patchset 1 (id:??) landed as
https://crrev.com/9528c9f4b7200659c10da799aaface62c19af91b
Cr-Commit-Position: refs/heads/master@{#341809}

[Zhenyao Mo, 2015-08-04 22:23:29]

Sample failure run:

https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win7/builds/33322