Add GN (the build tool) to the chromium.linux buildbots and try jobs

masters/master.chromium.linux/slaves.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # 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 master.experimental/slaves.cfg for documentation.
 
 
@@ skipping 90 matching lines @@
     'bits': '64',
   },
   {
     'master': 'ChromiumLinux',
     'builder': 'Linux Clang (dbg)',
     'hostname': 'build39-m1',
     'os': 'linux',
     'version': 'precise',
     'bits': '64',
   },
+  {
+    'master': 'ChromiumLinux',
+    'builder': 'Linux GN (dbg)',
+    'hostname': 'vm873-m1',
+    'os': 'linux',
+    'version': 'precise',
+    'bits': '64',
+  },
 ################################################################################
 # Android
 ################################################################################
   {
     'master': 'ChromiumLinux',
     'hostname': 'build1-a1',
     'builder': 'Android Builder (dbg)',
     'os': 'linux',
     'version': 'precise',
     'bits': '64',
@@ skipping 32 matching lines @@
   },
   {
     'master': 'ChromiumLinux',
     'builder': 'Android Webview AOSP Builder',
     'hostname': 'vm945-m1',
     'os': 'linux',
     'version': 'precise',
     'bits': '64',
   },
 ]