Adds simple browser-side implementation for DNS prefetching.

components/dns_prefetch.gypi

 # Copyright 2014 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.
 
 {
   'targets': [
     {
       # GN version: //components/dns_prefetch/common
       'target_name': 'dns_prefetch_common',
       'type': 'static_library',
       'include_dirs': [
         '..',
       ],
       'dependencies': [
         '../base/base.gyp:base',
       ],
       'sources': [
         'dns_prefetch/common/prefetch_common.cc',
         'dns_prefetch/common/prefetch_common.h',
         'dns_prefetch/common/prefetch_message_generator.cc',
         'dns_prefetch/common/prefetch_message_generator.h',
         'dns_prefetch/common/prefetch_messages.cc',
         'dns_prefetch/common/prefetch_messages.h',
       ],
     },
+    {
+      # GN version: //components/dns_prefetch/browser
+      'target_name': 'dns_prefetch_browser',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'dependencies': [
+        '../net/net.gyp:net',
+      ],
+      'sources': [
+        'dns_prefetch/browser/net_message_filter.cc',
+        'dns_prefetch/browser/net_message_filter.h',
+      ],
+    },
   ],
   'conditions': [
     ['OS!="ios"', {
       'targets': [
         {
           # GN version: //components/dns_prefetch/renderer
           'target_name': 'dns_prefetch_renderer',
           'type': 'static_library',
           'include_dirs': [
             '..',
           ],
           'dependencies': [
             'dns_prefetch_common',
             '../content/content.gyp:content_renderer',
           ],
           'sources': [
             'dns_prefetch/renderer/predictor_queue.cc',
             'dns_prefetch/renderer/predictor_queue.h',
             'dns_prefetch/renderer/renderer_net_predictor.cc',
             'dns_prefetch/renderer/renderer_net_predictor.h',
           ],
         },
       ],
     }],
   ],
 }