media: Prefer decrypting pipeline when CDM is attached

media/filters/decoder_selector.cc

Index: media/filters/decoder_selector.cc
diff --git a/media/filters/decoder_selector.cc b/media/filters/decoder_selector.cc
index 4ab98e20535228a630c7843ea5c7f34468a68e14..3d6854f3c5149a08fd94319d31aa4c4be9f485ea 100644
--- a/media/filters/decoder_selector.cc
+++ b/media/filters/decoder_selector.cc
@@ -40,19 +40,6 @@ static bool HasValidStreamConfig(DemuxerStream* stream) {
   return false;
 }
 
-static bool IsStreamEncrypted(DemuxerStream* stream) {
-  switch (stream->type()) {
-    case DemuxerStream::AUDIO:
-      return stream->audio_decoder_config().is_encrypted();
-    case DemuxerStream::VIDEO:
-      return stream->video_decoder_config().is_encrypted();
-    case DemuxerStream::TEXT:
-    case DemuxerStream::UNKNOWN:
-      NOTREACHED();
-  }
-  return false;
-}
-
 template <DemuxerStream::Type StreamType>
 DecoderSelector<StreamType>::DecoderSelector(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
@@ -106,23 +93,23 @@ void DecoderSelector<StreamType>::SelectDecoder(
   input_stream_ = stream;
   output_cb_ = output_cb;
 
-  if (!IsStreamEncrypted(input_stream_)) {
-    InitializeDecoder();
+  // When there is a CDM attached, always try the decrypting decoder or
+  // demuxer-stream first.
+  if (cdm_context_) {
+#if !defined(OS_ANDROID)
+    InitializeDecryptingDecoder();
+#else
+    InitializeDecryptingDemuxerStream();
+#endif
     return;
   }
 
-  // This could be null during fallback after decoder reinitialization failure.
-  // See DecoderStream<StreamType>::OnDecoderReinitialized().
-  if (!cdm_context_) {
-    ReturnNullDecoder();
-    return;
-  }
+  config_ = StreamTraits::GetDecoderConfig(input_stream_);
 
-#if !defined(OS_ANDROID)
-  InitializeDecryptingDecoder();
-#else
-  InitializeDecryptingDemuxerStream();
-#endif
+  // If the input stream is encrypted, CdmContext must be non-null.
+  DCHECK(!config_.is_encrypted());
+
+  InitializeDecoder();
 }
 
 #if !defined(OS_ANDROID)
@@ -177,6 +164,7 @@ void DecoderSelector<StreamType>::DecryptingDemuxerStreamInitDone(
   DVLOG(2) << __func__
            << ": status=" << MediaLog::PipelineStatusToString(status);
   DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(cdm_context_);
 
   // If DecryptingDemuxerStream initialization succeeded, we'll use it to do
   // decryption and use a decoder to decode the clear stream. Otherwise, we'll
@@ -185,10 +173,15 @@ void DecoderSelector<StreamType>::DecryptingDemuxerStreamInitDone(
 
   if (status == PIPELINE_OK) {
     input_stream_ = decrypted_stream_.get();
-    DCHECK(!IsStreamEncrypted(input_stream_));
+    config_ = StreamTraits::GetDecoderConfig(input_stream_);
+    DCHECK(!config_.is_encrypted());
   } else {
     decrypted_stream_.reset();
-    DCHECK(IsStreamEncrypted(input_stream_));
+    config_ = StreamTraits::GetDecoderConfig(input_stream_);
+
+    // Prefer decrypting decoder by using an encrypted config.
+    if (!config_.is_encrypted())
+      config_.SetIsEncrypted(true);
   }
 
   InitializeDecoder();
@@ -209,7 +202,7 @@ void DecoderSelector<StreamType>::InitializeDecoder() {
   decoders_.weak_erase(decoders_.begin());
 
   traits_->InitializeDecoder(
-      decoder_.get(), StreamTraits::GetDecoderConfig(input_stream_),
+      decoder_.get(), config_,
       input_stream_->liveness() == DemuxerStream::LIVENESS_LIVE, cdm_context_,
       base::Bind(&DecoderSelector<StreamType>::DecoderInitDone,
                  weak_ptr_factory_.GetWeakPtr()),