Replace deprecated base::NonThreadSafe in media/audio in favor of SequenceChecker.

media/audio/sounds/sounds_manager.h

Index: media/audio/sounds/sounds_manager.h
diff --git a/media/audio/sounds/sounds_manager.h b/media/audio/sounds/sounds_manager.h
index 004886d6c359fcaae64e9115e39555cb21e99751..6faf65231d3c521497d0e371ae663c7f78f0074d 100644
--- a/media/audio/sounds/sounds_manager.h
+++ b/media/audio/sounds/sounds_manager.h
@@ -7,8 +7,8 @@
 
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
+#include "base/sequence_checker.h"
 #include "base/strings/string_piece.h"
-#include "base/threading/non_thread_safe.h"
 #include "base/time/time.h"
 #include "media/base/media_export.h"
 
@@ -16,7 +16,7 @@ namespace media {
 
 // This class is used for reproduction of system sounds. All methods
 // should be accessed from the Audio thread.
-class MEDIA_EXPORT SoundsManager : public base::NonThreadSafe {
+class MEDIA_EXPORT SoundsManager {
  public:
   typedef int SoundKey;
 
@@ -55,6 +55,8 @@ class MEDIA_EXPORT SoundsManager : public base::NonThreadSafe {
   SoundsManager();
   virtual ~SoundsManager();
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
  private:
   DISALLOW_COPY_AND_ASSIGN(SoundsManager);
 };