Set the AudioManager factory before the browser main loop.

chromecast/browser/cast_content_browser_client.h

Index: chromecast/browser/cast_content_browser_client.h
diff --git a/chromecast/browser/cast_content_browser_client.h b/chromecast/browser/cast_content_browser_client.h
index 0d25e61f31ae1e9efd88f4e9665dc34d01253d28..5e5c262f92a103087e4856b5e9ec9a72bf0bc45f 100644
--- a/chromecast/browser/cast_content_browser_client.h
+++ b/chromecast/browser/cast_content_browser_client.h
@@ -6,6 +6,8 @@
 #define CHROMECAST_BROWSER_CAST_CONTENT_BROWSER_CLIENT_H_
 
 #include <map>
+#include <string>
+#include <vector>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
@@ -19,6 +21,10 @@ namespace content {
 class BrowserMessageFilter;
 }
 
+namespace media {
+class AudioManagerFactory;
+}
+
 namespace net {
 class HostResolver;
 }
@@ -109,6 +115,8 @@ class CastContentBrowserClient: public content::ContentBrowserClient {
       GURL requesting_url,
       int render_process_id);
 
+  scoped_ptr<::media::AudioManagerFactory> PlatformCreateAudioManagerFactory();
+
 #if !defined(OS_ANDROID)
   // Returns the crash signal FD corresponding to the current process type.
   int GetCrashSignalFD(const base::CommandLine& command_line);