media: Support better decoder switching

media/filters/decoder_selector.h

Index: media/filters/decoder_selector.h
diff --git a/media/filters/decoder_selector.h b/media/filters/decoder_selector.h
index 3ce4df6b201333d54617973dc02c8f7043a53598..51811d052c2008e0491cb6ac0ee4c925b15fa9d4 100644
--- a/media/filters/decoder_selector.h
+++ b/media/filters/decoder_selector.h
@@ -39,6 +39,11 @@ class MEDIA_EXPORT DecoderSelector {
   typedef typename StreamTraits::DecoderType Decoder;
   typedef typename StreamTraits::DecoderConfigType DecoderConfig;
 
+  // Callback to create a list of decoders to select from.
+  // TODO(xhwang): Use a DecoderFactory to create decoder one by one as needed,

[watk, 2017/05/04 21:35:33]

s/decoder/decoders/

[xhwang, 2017/05/04 23:53:13]

Done.

+  // instead of creating a list of decoders at once.

[watk, 2017/05/04 21:35:33]

s/at once/all at once/

[xhwang, 2017/05/04 23:53:13]

Done.

+  using CreateDecodersCB = base::RepeatingCallback<ScopedVector<Decoder>()>;
+
   // Indicates completion of Decoder selection.
   // - First parameter: The initialized Decoder. If it's set to NULL, then
   // Decoder initialization failed.
@@ -48,14 +53,13 @@ class MEDIA_EXPORT DecoderSelector {
   // Note: The caller owns selected Decoder and DecryptingDemuxerStream.
   // The caller should call DecryptingDemuxerStream::Reset() before
   // calling Decoder::Reset() to release any pending decryption or read.
-  typedef base::Callback<void(std::unique_ptr<Decoder>,
-                              std::unique_ptr<DecryptingDemuxerStream>)>
-      SelectDecoderCB;
+  using SelectDecoderCB =
+      base::Callback<void(std::unique_ptr<Decoder>,
+                          std::unique_ptr<DecryptingDemuxerStream>)>;
 
-  // |decoders| contains the Decoders to use when initializing.
   DecoderSelector(
-      const scoped_refptr<base::SingleThreadTaskRunner>& message_loop,
-      ScopedVector<Decoder> decoders,
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+      CreateDecodersCB create_decoders_cb,
       MediaLog* media_log);
 
   // Aborts pending Decoder selection and fires |select_decoder_cb| with
@@ -74,6 +78,7 @@ class MEDIA_EXPORT DecoderSelector {
   void SelectDecoder(StreamTraits* traits,
                      DemuxerStream* stream,
                      CdmContext* cdm_context,
+                     const std::string& blacklisted_decoder,
                      const SelectDecoderCB& select_decoder_cb,
                      const typename Decoder::OutputCB& output_cb,
                      const base::Closure& waiting_for_decryption_key_cb);
@@ -90,7 +95,7 @@ class MEDIA_EXPORT DecoderSelector {
   void ReturnNullDecoder();
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  ScopedVector<Decoder> decoders_;
+  CreateDecodersCB create_decoders_cb_;
   MediaLog* media_log_;
 
   StreamTraits* traits_;
@@ -100,10 +105,13 @@ class MEDIA_EXPORT DecoderSelector {
   DemuxerStream* input_stream_;
 
   CdmContext* cdm_context_;
+  std::string blacklisted_decoder_;
   SelectDecoderCB select_decoder_cb_;
   typename Decoder::OutputCB output_cb_;
   base::Closure waiting_for_decryption_key_cb_;
 
+  ScopedVector<Decoder> decoders_;
+
   std::unique_ptr<Decoder> decoder_;
   std::unique_ptr<DecryptingDemuxerStream> decrypted_stream_;