Build public cast_shell on x86 with GN.

chromecast/build/args.gn

Index: chromecast/build/args.gn
diff --git a/chromecast/build/args.gn b/chromecast/build/args.gn
index 54f0ca9e5b82cb520290be355c82eec3ed406bac..a768a59b23605aaf4d4394eade1ab6553664de65 100644
--- a/chromecast/build/args.gn
+++ b/chromecast/build/args.gn
@@ -11,9 +11,25 @@ enable_plugins = true
 enable_pepper_cdms = false
 
 # Flags set from build/common.gypi
+
+# Compile with MSE support for MPEG2 TS. See //media/media_options.gni for more
+# detail.
 enable_mpeg2ts_stream_parser = true
+
+# Instead of maintaining a separate "Chromecast" ffmpeg branding, "ChromeOS" is
+# used, as it sufficiently covers all the required codecs.
 ffmpeg_branding = "ChromeOS"
+
+# Setting this to true generates libeglplatform_shim.so.1 from
+# //ui/ozone/platform/egltest:egl_platform_x11.
+ozone_platform_ozonex = true
+
+# Chromecast must use proprietary codecs. Setting this to true defines the
+# USE_PROPRIETARY_CODECS macro and the proper EME_CODEC macros.
 proprietary_codecs = true
+
+# See //build/config/ui.gni. Notice that use_x11 = is_linux && !use_ozone.

[gunsch, 2015/08/05 02:04:10]

Are you saying we don't want use_x11 for our build?

[slan, 2015/08/05 14:34:58]

Correct, we are using ozone, with the egl_platform_x11 implementation:
https://code.google.com/p/chromium/codesearch#chromium/src/ui/ozone/platform/...

I will make sure that halliwell@ sees this before submit for visibility.

[slan, 2015/08/05 17:22:28]

lgtm from halliwell@ here.

+use_ozone = true
 # TODO(halliwell): look into supporting Cast Ozone with GN.
 # ozone_platform_cast = 1
 # TODO(gyp): Add support for blink_logging_always_on and enable it.