media: Prefer decrypting pipeline when CDM is attached

media/base/video_decoder_config.cc

Index: media/base/video_decoder_config.cc
diff --git a/media/base/video_decoder_config.cc b/media/base/video_decoder_config.cc
index a9dbcd21cf211321a1bb4f34f48086a82ffb351c..6e0c61fa372aa48dfbbcf19434a8bc6907884afc 100644
--- a/media/base/video_decoder_config.cc
+++ b/media/base/video_decoder_config.cc
@@ -7,6 +7,7 @@
 #include <vector>
 
 #include "base/logging.h"
+#include "media/base/media_util.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_types.h"
 
@@ -158,4 +159,19 @@ void VideoDecoderConfig::SetExtraData(const std::vector<uint8_t>& extra_data) {
   extra_data_ = extra_data;
 }
 
+void VideoDecoderConfig::SetIsEncrypted(bool is_encrypted) {
+  if (!is_encrypted) {
+    DCHECK(encryption_scheme_.is_encrypted()) << "Config is already clear.";
+    encryption_scheme_ = Unencrypted();
+  } else {
+    DCHECK(!encryption_scheme_.is_encrypted())
+        << "Config is already encrypted.";
+    // TODO(xhwang): This is only used to guide decoder selection, so set
+    // a common encryption scheme that should be supported by all decrypting
+    // decoders. We should be able to remove this when we support switching
+    // decoders at run time. See http://crbug.com/695595
+    encryption_scheme_ = AesCtrEncryptionScheme();
+  }
+}
+
 }  // namespace media