Remove failing CHECK(!delegate_) from SpdyStream::OnDataReceived()

Remove failing CHECK(!delegate_) from SpdyStream::OnDataReceived()

There is a race between SetDelegate() and the PushedStreamReplay() call
it posts a task for, and OnDataReceived() called as more data is
received over the network.  Specifically, if the latter is called after
SetDelegate() is called but before the task it posted has been executed,
the CHECK() fails.

BUG=356110
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=259800

[Jens Widell, 2014-03-25 11:56:25]

Please take a look.

Obviously, simply removing failing assertions isn't necessarily the right
approach; advise on other solutions is greatly appreciated.

I don't *think* anything actually goes wrong if the code after the CHECK() runs
in the case where it failed, but I'm in no way an expert here, of course.

[ramant (doing other things), 2014-03-25 16:07:20]

LGTM. Please get approval from jgraettinger@ also.

[Johnny, 2014-03-26 20:21:32]

LGTM

I don't see any problems introduced by this.

[Jens Widell, 2014-03-26 20:23:48]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-03-26 20:24:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jl@opera.com/210733006/1

[commit-bot: I haz the power, 2014-03-27 03:52:12]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-27 03:52:13]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[Jens Widell, 2014-03-27 05:44:05]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-03-27 05:44:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jl@opera.com/210733006/1

[commit-bot: I haz the power, 2014-03-27 05:45:49]

Change committed as 259800