Generalize AesDecryptor to make it more spec compliant.

media/mp4/mp4_stream_parser.h

Index: media/mp4/mp4_stream_parser.h
diff --git a/media/mp4/mp4_stream_parser.h b/media/mp4/mp4_stream_parser.h
index 269b9eb08f2409b2d1fa68454736816727efd6ca..5d0d0f93e217efae40e8fe29ab8785ce101aa6a2 100644
--- a/media/mp4/mp4_stream_parser.h
+++ b/media/mp4/mp4_stream_parser.h
@@ -28,7 +28,7 @@ class MEDIA_EXPORT MP4StreamParser : public StreamParser {
   virtual void Init(const InitCB& init_cb, const NewConfigCB& config_cb,
                     const NewBuffersCB& audio_cb,
                     const NewBuffersCB& video_cb,
-                    const KeyNeededCB& key_needed_cb,
+                    const NeedKeyCB& need_key_cb,
                     const NewMediaSegmentCB& new_segment_cb) OVERRIDE;
   virtual void Flush() OVERRIDE;
   virtual bool Parse(const uint8* buf, int size) OVERRIDE;
@@ -59,7 +59,7 @@ class MEDIA_EXPORT MP4StreamParser : public StreamParser {
   NewConfigCB config_cb_;
   NewBuffersCB audio_cb_;
   NewBuffersCB video_cb_;
-  KeyNeededCB key_needed_cb_;
+  NeedKeyCB need_key_cb_;
   NewMediaSegmentCB new_segment_cb_;
 
   OffsetByteQueue queue_;