Support HLS MPEG2 TS with SAMPLE-AES encryption.

media/media_options.gni

Index: media/media_options.gni
diff --git a/media/media_options.gni b/media/media_options.gni
index 40bfc89b85502ce39a982c91065af37bf588d6b9..b882ad68064f1dabe621c05bb332985be1fa6d54 100644
--- a/media/media_options.gni
+++ b/media/media_options.gni
@@ -44,6 +44,11 @@ declare_args() {
   # platform. Enable by default for Chromecast.
   enable_hevc_demuxing = proprietary_codecs && is_chromecast
 
+  # Enable HLS with SAMPLE-AES decryption. Actual decryption must be provided by
+  # the platform. Enabled by default on the cast desktop implementation to allow
+  # unit tests of the MP2TS parsing support.
+  enable_hls_sample_aes = proprietary_codecs && is_cast_desktop_build

[slan, 2016/03/18 22:31:23]

Hey Doug, I think we want to enable this by default on all Chromecast Linux A/V
devices (when using proprietary codecs). So perhaps we should make this:

enable_hls_sample_aes = is_chromecast && is_linux && 
                        proprietary_codecs && !disable_display

[dougsteed, 2016/03/21 18:11:06]

The intent was that the various OEMs would enable this explicitly when they
upgrade their code to support AES-CBC.

+
   # TODO(GYP): This should be a platform define.
   is_openbsd = false
 }