Refactor Pickle Read methods to use higher performance PickleIterator.

ipc/ipc_channel_posix.cc

 // Copyright (c) 2012 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_channel_posix.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <sys/types.h>
@@ skipping 690 matching lines @@
           }
 
           m.file_descriptor_set()->SetDescriptors(
               &fds[fds_i], header_fds);
           fds_i += header_fds;
         }
         DVLOG(2) << "received message on channel @" << this
                  << " with type " << m.type() << " on fd " << pipe_;
         if (IsHelloMessage(&m)) {
           // The Hello message contains only the process id.
-          void *iter = NULL;
+          PickleReader iter(m);
           int pid;
           if (!m.ReadInt(&iter, &pid)) {
             NOTREACHED();
           }
 #if defined(IPC_USES_READWRITE)
           if (mode_ & MODE_SERVER_FLAG) {
             // With IPC_USES_READWRITE, the Hello message from the client to the
             // server also contains the fd_pipe_, which  will be used for all
             // subsequent file descriptor passing.
             DCHECK_EQ(m.file_descriptor_set()->size(), 1U);
@@ skipping 531 matching lines @@
 }
 
 #if defined(OS_LINUX)
 // static
 void Channel::SetGlobalPid(int pid) {
   ChannelImpl::SetGlobalPid(pid);
 }
 #endif  // OS_LINUX
 
 }  // namespace IPC