[Chromecast] Add service for "displaying" cast web contents.

chromecast/chromecast.gni

Index: chromecast/chromecast.gni
diff --git a/chromecast/chromecast.gni b/chromecast/chromecast.gni
index 9de3efeae89948911e7c059c31a65fccb3f46be3..6f8137df7882701825c5e5f367bb7f782ac47736 100644
--- a/chromecast/chromecast.gni
+++ b/chromecast/chromecast.gni
@@ -24,6 +24,11 @@ declare_args() {
   # doing engineering builds.
   cast_is_debug = is_debug
 
+  if (is_android) {
+    # If true, run receiver apps in an Android service instead of an activity.
+    cast_android_use_service = false

[Simeon, 2017/05/15 19:47:24]

Do we want to enable this on audio-only builds yet?

[Simeon, 2017/05/15 19:47:24]

As for naming, how about display_web_contents_in_service? That's a bit more
clear about what the service is being used for.

[thoren, 2017/05/15 22:25:24]

Might as well I guess. The service-based approach is more stable on Things
anyway on account of the GPU issues.

[thoren, 2017/05/15 22:25:24]

Done.

+  }
+
   # If true, Chromecast WebUI resources are included in a build.
   # TODO(antz): default to false for audio-only builds, might need further
   # clean up (b/27119303)