Media Remoting: Add RemotingController.

content/renderer/BUILD.gn

Index: content/renderer/BUILD.gn
diff --git a/content/renderer/BUILD.gn b/content/renderer/BUILD.gn
index ca620ed678e164abf22a2c79ab68080a43f12f58..407229bc9229dfbcfd2f5940b01e9c7b070a9dbc 100644
--- a/content/renderer/BUILD.gn
+++ b/content/renderer/BUILD.gn
@@ -509,6 +509,12 @@ target(link_target_type, "renderer") {
     ]
   }
 
+  if (enable_media_remoting) {
+    deps += [ "//media/remoting" ]
+
+    defines += [ "ENABLE_MEDIA_REMOTING" ]

[xhwang, 2016/10/05 05:27:53]

This is the old way. For new code, please use BUILDFLAG:

https://cs.chromium.org/chromium/src/build/buildflag_header.gni?sq=package:ch...

Also, is it possible that you'll need to check this build flag in the browser
side as well (e.g. content/browser)? Since enable_media_remoting is declared in
media/, usually we define the buildflag in media/ as well. See this example:

https://cs.chromium.org/chromium/src/media/BUILD.gn?rcl=0&l=16

[xjz, 2016/10/05 17:24:23]

Done.

+  }
+
   if (enable_webrtc) {
     # WebRTC plugin-related stuff goes in a different section below.
     sources += [