net: fix DnsRRResolver on Mac.

net/base/dnsrr_resolver.cc

 // Copyright (c) 2010 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 "net/base/dnsrr_resolver.h"
 
 #if defined(OS_POSIX)
 #include <resolv.h>
 #endif
 
@@ skipping 481 matching lines @@
 
         if (jumps == 0) {
           p_ = p;
           len_ = len;
         }
         jumps++;
 
         if (offset >= packet_len_)
           return false;
         p = &packet_[offset];
+        len = packet_len_ - offset;
       } else if ((d & 0xc0) == 0) {
         uint8 label_len = d;
         if (len < label_len)
           return false;
         if (name && label_len) {
           if (!name->empty())
             name->append(".");
           name->append(reinterpret_cast<const char*>(p), label_len);
         }
         p += label_len;
@@ skipping 297 matching lines @@
   inflight_.erase(j);
 
   job->HandleResult(result, response);
   delete job;
 }
 
 }  // namespace net
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(net::RRResolverHandle);
 DISABLE_RUNNABLE_METHOD_REFCOUNT(net::RRResolverWorker);