Revert of Fix use-after-free in WebSocketHost::AddChannel()

Revert of Fix use-after-free in WebSocketHost::AddChannel() (patchset #3 id:40001 of https://codereview.chromium.org/998173003/)

Reason for revert:
Speculatively revert for https://crbug.com/467471

Original issue's description:
> Fix heap-use-after-free in WebSocketHost::AddChannel()
>
> WebSocketHost can be deleted in channel_->SendAddChannelRequest() and this
> caused heap-use-after-free when |pending_flow_control_quota_| is accessed in
> WebSocketHost::AddChannel().
> This CL fixes it by posting OnFlowControl() with WeakPtr instead of calling
> SendFlowControl() directly in WebSocketHost::AddChannel().
>
> BUG=466335
>
> Committed: https://crrev.com/d3a1d188162e45f75c87a218a70681c5d92139a8
> Cr-Commit-Position: refs/heads/master@{#320260}

TBR=ricea@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=466335
Committed: https://crrev.com/4f078b9b59cbf2c1ea7098835c6488fa32d46474
Cr-Commit-Position: refs/heads/master@{#320703}

[hiroshige, 2015-03-16 10:29:07]

Created Revert of Fix use-after-free in WebSocketHost::AddChannel()

[commit-bot: I haz the power, 2015-03-16 10:29:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1006293002/1

[commit-bot: I haz the power, 2015-03-16 10:29:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-16 10:30:10]

Patchset 1 (id:??) landed as
https://crrev.com/4f078b9b59cbf2c1ea7098835c6488fa32d46474
Cr-Commit-Position: refs/heads/master@{#320703}

[hiroshige, 2015-03-16 12:56:46]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1014543002/ by hiroshige@chromium.org.

The reason for reverting is: The breakage still persists
https://crbug.com/467471 after the original CL was reverted..