Set the AudioManager factory before the browser main loop.

chromecast/browser/cast_content_browser_client_simple.cc

Index: chromecast/browser/cast_content_browser_client_simple.cc
diff --git a/chromecast/browser/cast_content_browser_client_simple.cc b/chromecast/browser/cast_content_browser_client_simple.cc
index 34012b4d83357b5941723af4b8d118cd5b006933..bde5a71d028865098286a23615b9c04678e3b76a 100644
--- a/chromecast/browser/cast_content_browser_client_simple.cc
+++ b/chromecast/browser/cast_content_browser_client_simple.cc
@@ -5,6 +5,7 @@
 #include "chromecast/browser/cast_content_browser_client.h"
 
 #include "content/public/browser/browser_message_filter.h"
+#include "media/audio/audio_manager_factory.h"
 
 namespace chromecast {
 namespace shell {
@@ -18,5 +19,12 @@ CastContentBrowserClient::PlatformGetBrowserMessageFilters() {
   return std::vector<scoped_refptr<content::BrowserMessageFilter>>();
 }
 
+scoped_ptr<::media::AudioManagerFactory>
+CastContentBrowserClient::PlatformCreateAudioManagerFactory() {
+  // Return nullptr. The factory will not be set, and the statically linked
+  // implementation of AudioManager will be used.
+  return scoped_ptr<::media::AudioManagerFactory>();
+}
+
 }  // namespace shell
 }  // namespace chromecast