Convert over to channel handles

This hides some of the internals of the posix channels from users, and gets rid
of several #ifdef POSIX blocks. Generally simplifies usage of channels xplatform.

BUG=none
TEST=build

Review URL: http://codereview.chromium.org/5598010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68621 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ipc/ipc_sync_channel.cc b/ipc/ipc_sync_channel.cc
index e77846c..7425a9b 100644
--- a/ipc/ipc_sync_channel.cc
+++ b/ipc/ipc_sync_channel.cc
@@ -355,14 +355,14 @@
 
 
 SyncChannel::SyncChannel(
-    const std::string& channel_id,
+    const IPC::ChannelHandle& channel_handle,
     Channel::Mode mode,
     Channel::Listener* listener,
     MessageLoop* ipc_message_loop,
     bool create_pipe_now,
     WaitableEvent* shutdown_event)
     : ChannelProxy(
-          channel_id, mode, ipc_message_loop,
+          channel_handle, mode, ipc_message_loop,
           new SyncContext(listener, ipc_message_loop, shutdown_event),
           create_pipe_now),
       sync_messages_with_no_timeout_allowed_(true) {