Don't resolve IP literals.

net/base/host_resolver_impl.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/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 736 matching lines @@
   if (cur_completing_job_)
     cur_completing_job_->Cancel();
 
   NetworkChangeNotifier::RemoveObserver(this);
 
   // Delete the job pools.
   for (size_t i = 0u; i < arraysize(job_pools_); ++i)
     delete job_pools_[i];
 }
 
-// TODO(eroman): Don't create cache entries for hostnames which are simply IP
-// address literals.
 int HostResolverImpl::Resolve(const RequestInfo& info,
                               AddressList* addresses,
                               CompletionCallback* callback,
                               RequestHandle* out_req,
                               const BoundNetLog& net_log) {
   DCHECK(CalledOnValidThread());
 
   if (shutdown_)
     return ERR_UNEXPECTED;
 
   // Choose a unique ID number for observers to see.
   int request_id = next_request_id_++;
 
   // Update the net log and notify registered observers.
   OnStartRequest(net_log, request_id, info);
 
+  // Check for IP literal.
+  IPAddressNumber ip_number;
+  if (ParseIPLiteralToNumber(info.hostname(), &ip_number)) {
+    DCHECK_EQ((info.host_resolver_flags() &
+               ~(HOST_RESOLVER_CANONNAME | HOST_RESOLVER_LOOPBACK_ONLY)), 0)
+        << " Unhandled flag";
+    AddressList result(ip_number, info.port(),
+                       (info.host_resolver_flags() & HOST_RESOLVER_CANONNAME));
+
+    *addresses = result;
+    // Update the net log and notify registered observers.
+    OnFinishRequest(net_log, request_id, info, OK,
+                    0,  /* os_error (unknown since from cache) */
+                    false  /* was_from_cache */);
+    return OK;
+  }
+
   // Build a key that identifies the request in the cache and in the
   // outstanding jobs map.
   Key key = GetEffectiveKeyForRequest(info);
 
   // If we have an unexpired cache entry, use it.
   if (info.allow_cached_response() && cache_.get()) {
     const HostCache::Entry* cache_entry = cache_->Lookup(
         key, base::TimeTicks::Now());
     if (cache_entry) {
       int net_error = cache_entry->error;
@@ skipping 383 matching lines @@
     if (r == req)
       return error;
 
     r->OnComplete(error, AddressList());
   }
 
   return ERR_IO_PENDING;
 }
 
 }  // namespace net