Chromecast: adds a few dummy GYP targets for easier internal build.

R=byungchul@chromium.org,servolk@chromium.org
TBR=lcwu@chromium.org
BUG=

Review URL: https://codereview.chromium.org/822803002

Cr-Commit-Position: refs/heads/master@{#309574}
diff --git a/chromecast/chromecast.gyp b/chromecast/chromecast.gyp
index d9cc401..9f9a88f 100644
--- a/chromecast/chromecast.gyp
+++ b/chromecast/chromecast.gyp
@@ -18,6 +18,11 @@
     ],
   },
   'targets': [
+    # TODO(gunsch): Remove these fake targets once they're either added or no
+    # longer referenced from internal code.
+    {'target_name': 'cast_media_audio', 'type': 'none'},
+    {'target_name': 'cast_port_impl', 'type': 'none'},
+
     {
       'target_name': 'cast_base',
       'type': '<(component)',