Revert of IPC: Add attachment brokering support to the message header. (patchset #20 id:420001 of https://codereview.chromium.org/1286253002/ )

Reason for revert:
Suspected of breaking XP Tests. See, for example https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/39586 .

Original issue's description:
> IPC: Add attachment brokering support to the message header.
>
> Message dispatch happens before message translation, and message dispatch
> requires that all brokered attachments have been received. This means that
> attachment brokering needs to function without message translation. This is
> accomplished by modifying the message header to include a new field
> num_brokered_attachments, and writing the attachment ids into the IPC Channel
> immediately following the pickled message itself.
>
> AttachmentBrokerPrivilegedWinUnittest was expanded to test ChannelReader in the
> receiving process. It is now a fully functional end-to-end test of attachment
> brokering.
>
> BUG=493414
>
> Committed: https://crrev.com/e8e4f4fa67ee9db6c2910020ef49318e5df68481
> Cr-Commit-Position: refs/heads/master@{#344389}

TBR=tsepez@chromium.org,thakis@chromium.org,erikchen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=493414

Review URL: https://codereview.chromium.org/1286883003

Cr-Commit-Position: refs/heads/master@{#344461}

1 files changed, 0 insertions, 1 deletions

diff --git a/ipc/ipc_channel_posix.cc b/ipc/ipc_channel_posix.cc
index 977db22..b5e2332 100644
--- a/ipc/ipc_channel_posix.cc
+++ b/ipc/ipc_channel_posix.cc
@@ -205,7 +205,6 @@ ChannelPosix::ChannelPosix(const IPC::ChannelHandle& channel_handle,
 
 ChannelPosix::~ChannelPosix() {
   in_dtor_ = true;
-  CleanUp();
   Close();
 }