Add decoder-specific settings with proper lifetime.

webrtc/config.h

Index: webrtc/config.h
diff --git a/webrtc/config.h b/webrtc/config.h
index b2dfe2d272642fa5b8f73bd4a0e75b4a3c4925d1..a465d30af354098c83ebe3ec840d301ff26e0c4d 100644
--- a/webrtc/config.h
+++ b/webrtc/config.h
@@ -16,6 +16,7 @@
 #include <string>
 #include <vector>
 
+#include "webrtc/base/optional.h"
 #include "webrtc/common.h"
 #include "webrtc/common_types.h"
 #include "webrtc/typedefs.h"
@@ -146,6 +147,17 @@ struct VideoEncoderConfig {
   bool expect_encode_from_texture;
 };
 
+struct VideoDecoderH264extraSettings {

[stefan-webrtc, 2016/08/01 10:58:09]

H264Extra

Is it necessary to even mention "Extra"? :)

[johan, 2016/08/01 12:08:04]

You have a point. ;-)

+  std::string spropParameterSets;

[stefan-webrtc, 2016/08/01 10:58:09]

no camel case style

[johan, 2016/08/01 12:08:04]

Done.

+};
+
+class DecoderSpecificSettings {
+ public:
+  virtual ~DecoderSpecificSettings() {}
+  rtc::Optional<VideoDecoderH264extraSettings> h264_extra_settings;
+  // vp8_extra_settings, and vp9_extra_settings will be added when required

[stefan-webrtc, 2016/08/01 10:58:09]

remove this comment

[johan, 2016/08/01 12:08:04]

Done.

+};
+
 // Controls the capacity of the packet buffer in NetEq. The capacity is the
 // maximum number of packets that the buffer can contain. If the limit is
 // exceeded, the buffer will be flushed. The capacity does not affect the actual