fix the shared build

TBR=henrika

Review URL: https://chromiumcodereview.appspot.com/10533044

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@140997 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/media/audio/async_socket_io_handler.h b/media/audio/async_socket_io_handler.h
index 463b2ca..0bbb5c1 100644
--- a/media/audio/async_socket_io_handler.h
+++ b/media/audio/async_socket_io_handler.h
@@ -50,8 +50,8 @@
 // };
 //
 class MEDIA_EXPORT AsyncSocketIoHandler
-    : public base::NonThreadSafe,
-      public MessageLoopIOHandler {
+    : public NON_EXPORTED_BASE(base::NonThreadSafe),
+      public NON_EXPORTED_BASE(MessageLoopIOHandler) {
  public:
   AsyncSocketIoHandler();
   virtual ~AsyncSocketIoHandler();