Revert of Add ChannelPosix::ResetSafely() to deal with a lingering crash

Revert of Add ChannelPosix::ResetSafely() to deal with a lingering crash (patchset #1 id:1 of https://codereview.chromium.org/882543002/)

Reason for revert:
many ipc test failed.
https://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%281%29/builds/10036

Original issue's description:
> Add ChannelPosix::ResetSafely() to deal with a lingering crash
>
> The CL [1] tightened the error check too much and revealed
> an existing inconsistency and resulted a production crash.
> This CL makes a workaround to that crash, turning a PCHECK()
> to DPCHECK().
>
> [1] https://crrev.com/ce44fef5fd60dd2be5c587d4b084bdcd36adcee4
>
> BUG=449233, 448245
> R=agl@chromium.org,jam@chromium.org
>
> Committed: https://crrev.com/cf3eae19b456536c5ff8dacf8800ec09f9af4bca
> Cr-Commit-Position: refs/heads/master@{#313188}

TBR=agl@chromium.org,jam@chromium.org,morrita@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=449233, 448245
Committed: https://crrev.com/b83c03c7b691914a054abaab13fb9131b4e0152b
Cr-Commit-Position: refs/heads/master@{#313226}

[yoichio, 2015-01-27 04:15:05]

Created Revert of Add ChannelPosix::ResetSafely() to deal with a lingering crash

[commit-bot: I haz the power, 2015-01-27 04:15:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/878843002/1

[commit-bot: I haz the power, 2015-01-27 04:17:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-27 04:21:41]

Patchset 1 (id:??) landed as
https://crrev.com/b83c03c7b691914a054abaab13fb9131b4e0152b
Cr-Commit-Position: refs/heads/master@{#313226}