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 1108 matching lines @@
 void Channel::ChannelImpl::ClearInputFDs() {
   while (!input_fds_.empty()) {
     if (HANDLE_EINTR(close(input_fds_.front())) < 0)
       PLOG(ERROR) << "close ";
     input_fds_.pop_front();
   }
 }
 
 void Channel::ChannelImpl::HandleHelloMessage(const Message& msg) {
   // The Hello message contains only the process id.
-  void *iter = NULL;
+  PickleIterator iter(msg);
   int pid;
   if (!msg.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(msg.file_descriptor_set()->size(), 1U);
@@ skipping 86 matching lines @@
 }
 
 #if defined(OS_LINUX)
 // static
 void Channel::SetGlobalPid(int pid) {
   ChannelImpl::SetGlobalPid(pid);
 }
 #endif  // OS_LINUX
 
 }  // namespace IPC