This patch caused Chrome to be unable to load any web pages on Chrome OS.

ipc/ipc_sync_channel.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ipc/ipc_sync_channel.h"
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/threading/thread_local.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 359 matching lines @@
 
 SyncChannel::SyncChannel(
     const IPC::ChannelHandle& channel_handle,
     Channel::Mode mode,
     Channel::Listener* listener,
     base::MessageLoopProxy* ipc_message_loop,
     bool create_pipe_now,
     WaitableEvent* shutdown_event)
     : ChannelProxy(
           channel_handle, mode, ipc_message_loop,
-          false /* needs_override_peer_pid */,
           new SyncContext(listener, ipc_message_loop, shutdown_event),
           create_pipe_now),
       sync_messages_with_no_timeout_allowed_(true) {
   // Ideally we only want to watch this object when running a nested message
   // loop.  However, we don't know when it exits if there's another nested
   // message loop running under it or not, so we wouldn't know whether to
   // stop or keep watching.  So we always watch it, and create the event as
   // manual reset since the object watcher might otherwise reset the event
   // when we're doing a WaitMany.
   dispatch_watcher_.StartWatching(sync_context()->GetDispatchEvent(), this);
@@ skipping 114 matching lines @@
 void SyncChannel::OnWaitableEventSignaled(WaitableEvent* event) {
   DCHECK(event == sync_context()->GetDispatchEvent());
   // The call to DispatchMessages might delete this object, so reregister
   // the object watcher first.
   event->Reset();
   dispatch_watcher_.StartWatching(event, this);
   sync_context()->DispatchMessages();
 }
 
 }  // namespace IPC