Remove unused code and exclude unused files on Chrome OS too.

net/net.gyp

Index: net/net.gyp
diff --git a/net/net.gyp b/net/net.gyp
index 0971ebee1ab53dd83fcbc2a3c659f8615d71f0f0..15690c03c03f4e35404c8e4ab4421ed2b3a2634d 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -795,6 +795,10 @@
       'conditions': [
         ['chromeos==1', {
           'sources!': [
+             'base/network_change_notifier_linux.cc',
+             'base/network_change_notifier_linux.h',
+             'base/network_change_notifier_netlink_linux.cc',
+             'base/network_change_notifier_netlink_linux.h',
              'proxy/proxy_config_service_linux.cc',
              'proxy/proxy_config_service_linux.h',
           ],
@@ -1270,6 +1274,7 @@
       'conditions': [
         ['chromeos==1', {
           'sources!': [
+             'base/network_change_notifier_linux_unittest.cc',
              'proxy/proxy_config_service_linux_unittest.cc',
           ],
         }],