Do not require a key before processing unencrypted frames within a potentially encrypted stream.

media/crypto/aes_decryptor.cc

Index: media/crypto/aes_decryptor.cc
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index 83f818e60d015118785d090f1b31c35e786195d3..324d955e9f8a98d75335d6f0be13405dc4d2f46c 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -234,13 +234,6 @@ void AesDecryptor::Decrypt(StreamType stream_type,
   CHECK(encrypted->GetDecryptConfig());
   const std::string& key_id = encrypted->GetDecryptConfig()->key_id();
 
-  DecryptionKey* key = GetKey(key_id);
-  if (!key) {
-    DVLOG(1) << "Could not find a matching key for the given key ID.";
-    decrypt_cb.Run(kNoKey, NULL);
-    return;
-  }
-
   scoped_refptr<DecoderBuffer> decrypted;
   // An empty iv string signals that the frame is unencrypted.
   if (encrypted->GetDecryptConfig()->iv().empty()) {
@@ -248,6 +241,13 @@ void AesDecryptor::Decrypt(StreamType stream_type,
     decrypted = DecoderBuffer::CopyFrom(encrypted->GetData() + data_offset,
                                         encrypted->GetDataSize() - data_offset);
   } else {

[xhwang, 2013/01/09 21:18:21]

move line 235 here?

[ddorwin, 2013/01/10 04:44:46]

Done.

+    DecryptionKey* key = GetKey(key_id);
+    if (!key) {
+      DVLOG(1) << "Could not find a matching key for the given key ID.";
+      decrypt_cb.Run(kNoKey, NULL);
+      return;
+    }
+
     crypto::SymmetricKey* decryption_key = key->decryption_key();
     decrypted = DecryptData(*encrypted, decryption_key);
     if (!decrypted) {