DNS Prefetch fix: renderer shouldn't send long hostnames to browser.

components/network_hints/renderer/renderer_dns_prefetch.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.
 
 // See header file for description of RendererDnsPrefetch class
 
 #include "components/network_hints/renderer/renderer_dns_prefetch.h"
 
 #include <ctype.h>
 
@@ skipping 112 matching lines @@
       --count;
     } else {
       DCHECK(kPending == it->second || kLookupRequested == it->second);
     }
   }
 }
 
 void RendererDnsPrefetch::DnsPrefetchNames(size_t max_count) {
   // We are on the renderer thread, and just need to send things to the browser.
   NameList names;
+  size_t domains_handled = 0;
   for (DomainUseMap::iterator it = domain_map_.begin();
     it != domain_map_.end();
     ++it) {
     if (0 == (it->second & kLookupRequested)) {
       it->second |= kLookupRequested;
-      names.push_back(it->first);
+      domains_handled++;
+      if (it->first.length() <= network_hints::kMaxDnsHostnameLength)
+        names.push_back(it->first);
       if (0 == max_count) continue;  // Get all, independent of count.
       if (1 == max_count) break;
       --max_count;
       DCHECK_GE(max_count, 1u);
     }
   }
-  DCHECK_GE(new_name_count_, names.size());
-  new_name_count_ -= names.size();
+  DCHECK_GE(new_name_count_, domains_handled);
+  new_name_count_ -= domains_handled;
 
   network_hints::LookupRequest request;
   request.hostname_list = names;
   RenderThread::Get()->Send(new NetworkHintsMsg_DNSPrefetch(request));
 }
 
 // is_numeric_ip() checks to see if all characters in name are either numeric,
 // or dots.  Such a name will not actually be passed to DNS, as it is an IP
 // address.
 bool RendererDnsPrefetch::is_numeric_ip(const char* name, size_t length) {
   // Scan for a character outside our lookup list.
   while (length-- > 0) {
     if (!isdigit(*name) && '.' != *name)
       return false;
     ++name;
   }
   return true;
 }
 
 }  // namespace predictor