Convert GN visibility to be a list.

GN visibility currently allows either string or list types, but this is causing
some problems for some templates. I'm going to require it to be lists, so am
changing all callers before pushing the new binary.

R=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25439004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7111 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_conference_mixer/BUILD.gn b/webrtc/modules/audio_conference_mixer/BUILD.gn
index c27d184..a94d005 100644
--- a/webrtc/modules/audio_conference_mixer/BUILD.gn
+++ b/webrtc/modules/audio_conference_mixer/BUILD.gn
@@ -7,7 +7,7 @@
 # be found in the AUTHORS file in the root of the source tree.
 
 config("internal_config") {
-  visibility = ":*"  # Only targets in this file can depend on this.
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
   include_dirs = [
     "interface",
     "../interface",
diff --git a/webrtc/modules/media_file/BUILD.gn b/webrtc/modules/media_file/BUILD.gn
index 4e0cac6..6f49dcd 100644
--- a/webrtc/modules/media_file/BUILD.gn
+++ b/webrtc/modules/media_file/BUILD.gn
@@ -9,7 +9,7 @@
 import("../../build/webrtc.gni")
 
 config("internal_config") {
-  visibility = ":*"  # Only targets in this file can depend on this.
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
   include_dirs = [
     "interface",
     "../interface",