Add DiscoveryNetworkMonitor implementation

chrome/browser/media/router/discovery/BUILD.gn

Index: chrome/browser/media/router/discovery/BUILD.gn
diff --git a/chrome/browser/media/router/discovery/BUILD.gn b/chrome/browser/media/router/discovery/BUILD.gn
index 21199e1256b57de557877a972fafae8d49e09d87..212144456e0b77478c2f199e82a6288b4dc0d04a 100644
--- a/chrome/browser/media/router/discovery/BUILD.gn
+++ b/chrome/browser/media/router/discovery/BUILD.gn
@@ -33,4 +33,17 @@ static_library("discovery") {
     "dial/safe_dial_device_description_parser.cc",
     "dial/safe_dial_device_description_parser.h",
   ]
+
+  if (!is_android) {
+    sources += [
+      "discovery_network_info.cpp",
+      "discovery_network_info.h",
+      "discovery_network_list.h",
+      "discovery_network_list_posix.cc",

[imcheng, 2017/05/26 23:49:00]

It seems we should put platform specific files into conditionals?

[btolsch, 2017/05/30 09:54:29]

Files like *_posix.cc are filtered out by sources_assignment_filter (
https://cs.chromium.org/chromium/src/build/config/BUILDCONFIG.gn?q=buildconfi...
).  Are you suggesting it should be in a separate if() block for style reasons?

[imcheng, 2017/05/31 21:19:55]

Ah ok. I didn't know about source_assignment_filter. It is fine to leave it as
is.

+      "discovery_network_list_wifi.h",
+      "discovery_network_list_wifi_linux.cc",
+      "discovery_network_monitor.cc",
+      "discovery_network_monitor.h",
+    ]
+  }
 }