media config: expand is_encrypted to a struct.

media/base/audio_decoder_config.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
 #define MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
 
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "media/base/channel_layout.h"
+#include "media/base/encryption_scheme.h"
 #include "media/base/media_export.h"
 #include "media/base/sample_format.h"
 
 namespace media {
 
 enum AudioCodec {
   // These values are histogrammed over time; do not change their ordinal
   // values.  When deleting a codec replace it with a dummy value; when adding a
   // codec, do so at the bottom before kAudioCodecMax, and update the value of
   // kAudioCodecMax to equal the new codec.
@@ skipping 33 matching lines @@
   // Constructs an uninitialized object. Clients should call Initialize() with
   // appropriate values before using.
   AudioDecoderConfig();
 
   // Constructs an initialized object.
   AudioDecoderConfig(AudioCodec codec,
                      SampleFormat sample_format,
                      ChannelLayout channel_layout,
                      int samples_per_second,
                      const std::vector<uint8_t>& extra_data,
-                     bool is_encrypted);
+                     const EncryptionScheme& encryption_scheme);
 
   ~AudioDecoderConfig();
 
   // Resets the internal state of this object. |codec_delay| is in frames.
   void Initialize(AudioCodec codec,
                   SampleFormat sample_format,
                   ChannelLayout channel_layout,
                   int samples_per_second,
                   const std::vector<uint8_t>& extra_data,
-                  bool is_encrypted,
+                  const EncryptionScheme& encryption_scheme,
                   base::TimeDelta seek_preroll,
                   int codec_delay);
 
   // Returns true if this object has appropriate configuration values, false
   // otherwise.
   bool IsValidConfig() const;
 
   // Returns true if all fields in |config| match this config.
   // Note: The contents of |extra_data_| are compared not the raw pointers.
   bool Matches(const AudioDecoderConfig& config) const;
@@ skipping 12 matching lines @@
   base::TimeDelta seek_preroll() const { return seek_preroll_; }
   int codec_delay() const { return codec_delay_; }
 
   // Optional byte data required to initialize audio decoders such as Vorbis
   // codebooks.
   const std::vector<uint8_t>& extra_data() const { return extra_data_; }
 
   // Whether the audio stream is potentially encrypted.
   // Note that in a potentially encrypted audio stream, individual buffers
   // can be encrypted or not encrypted.
-  bool is_encrypted() const { return is_encrypted_; }
+  bool is_encrypted() const;

[ddorwin, 2016/03/01 02:17:41]

My concern in PS1 of cast_audio_output_stream_unittest.cc was really about this
change (and the corresponding one for video).

We may have tests calling is_encrypted() on the config, and these will continue
to compile without changes. However, we really should be checking all properties
of the scheme. We should try to identify and update those tests.

[dougsteed, 2016/03/02 18:07:52]

It seems to me that generally in the code (there are 67 places in 30 files where
is_encrypted() is called) the caller is interested in just the boolean, not the
details. For example, in many contexts, both in the actual code and in
unittests, encryption is not allowed or supported, so being able to test that
is_encrypted() is false seems very appropriate. In those contexts there is
nothing to be gained in checking the mode or pattern.

[ddorwin, 2016/03/02 23:24:05]

Okay. I guess we should look for places where we expect it to be true in tests
and then check the other members in those cases.

+
+  // Encryption scheme used for encrypted buffers.
+  const EncryptionScheme& encryption_scheme() const {
+    return encryption_scheme_;
+  }
 
  private:
   AudioCodec codec_;
   SampleFormat sample_format_;
   int bytes_per_channel_;
   ChannelLayout channel_layout_;
   int samples_per_second_;
   int bytes_per_frame_;
   std::vector<uint8_t> extra_data_;
-  bool is_encrypted_;
+  EncryptionScheme encryption_scheme_;
 
   // |seek_preroll_| is the duration of the data that the decoder must decode
   // before the decoded data is valid.
   base::TimeDelta seek_preroll_;
 
   // |codec_delay_| is the number of frames the decoder should discard before
   // returning decoded data.  This value can include both decoder delay as well
   // as padding added during encoding.
   int codec_delay_;
 
   // Not using DISALLOW_COPY_AND_ASSIGN here intentionally to allow the compiler
   // generated copy constructor and assignment operator. Since the extra data is
   // typically small, the performance impact is minimal.
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_DECODER_CONFIG_H_