Generalize AesDecryptor to make it more spec compliant.

media/webm/webm_stream_parser.h

Index: media/webm/webm_stream_parser.h
diff --git a/media/webm/webm_stream_parser.h b/media/webm/webm_stream_parser.h
index 003171e555b6798c1ebd710a5a97e3b46e2fb8b5..f5552781bb2a0cf96464d0af02475f3f6147b7ca 100644
--- a/media/webm/webm_stream_parser.h
+++ b/media/webm/webm_stream_parser.h
@@ -25,7 +25,7 @@ class WebMStreamParser : 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;
@@ -64,7 +64,7 @@ class WebMStreamParser : public StreamParser {
   NewConfigCB config_cb_;
   NewBuffersCB audio_cb_;
   NewBuffersCB video_cb_;
-  KeyNeededCB key_needed_cb_;
+  NeedKeyCB need_key_cb_;
   NewMediaSegmentCB new_segment_cb_;
 
   // True if a new cluster id has been seen, but no audio or video buffers have