Fix Eureka Roll Failure

Change-Id: If0b1a475873d886f36d3ed1a6231f881ec73d30e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2596112Reviewed-by: Sean Topping <seantopping@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Yuchen Liu <yucliu@chromium.org>
Auto-Submit: Ryan Keane <rwkeane@google.com>
Cr-Commit-Position: refs/heads/master@{#837994}

chromecast/media/cma/backend/proxy/BUILD.gn

@@ -58,7 +58,8 @@ cast_source_set("proxy") {
     "//third_party/protobuf:protobuf_full",
   ]
 
-  if (chromecast_branding == "public") {
+  if (!enable_chromium_runtime_cast_renderer ||
+      chromecast_branding == "public") {
     sources += [ "audio_channel_broker_simple.cc" ]
   }
 }