Avoid heap allocations in IPAddress

net/quic/platform/impl/quic_ip_address_impl.cc

 // Copyright (c) 2016 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/quic/platform/impl/quic_ip_address_impl.h"
 
 #include "net/base/address_family.h"
 #include "net/quic/platform/api/quic_bug_tracker.h"
 
 #if defined(OS_WIN)
@@ skipping 89 matching lines @@
   }
   return QuicIpAddressImpl(ip_address_);
 }
 
 bool QuicIpAddressImpl::FromPackedString(const char* data, size_t length) {
   if (length != IPAddress::kIPv4AddressSize &&
       length != IPAddress::kIPv6AddressSize) {
     QUIC_BUG << "Invalid packed IP address of length " << length;
     return false;
   }
-  std::vector<uint8_t> ip(length);
-  memcpy(&ip[0], data, length);
-  ip_address_ = IPAddress(ip);
+  ip_address_ = IPAddress(reinterpret_cast<const uint8_t*>(data), length);
   return true;
 }
 
 bool QuicIpAddressImpl::FromString(string str) {
   return ip_address_.AssignFromIPLiteral(str);
 }
 
 bool QuicIpAddressImpl::IsIPv4() const {
   return ip_address_.IsIPv4();
 }
 
 bool QuicIpAddressImpl::IsIPv6() const {
   return ip_address_.IsIPv6();
 }
 
 bool QuicIpAddressImpl::InSameSubnet(const QuicIpAddressImpl& other,
                                      int subnet_length) {
   return IPAddressMatchesPrefix(ip_address_, other.ip_address(), subnet_length);
 }
 
 }  // namespace net