Implemented HEVC video demuxing and parsing

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 948dcece70dcd3ca0944135682591ff6440b9054..0af4545a6d10a55c710c97b65f1b0de27daca8a0 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1472,6 +1472,14 @@
     # Set to 1 to compile with MSE support for MPEG2 TS
     'enable_mpeg2ts_stream_parser%': 0,
 
+    # HEVC/H265 demuxing support. For HEVC demuxing support in MediaSource/MSE
+    # changing this flag is sufficient. But when using FFmpegDemuxer, e.g. when
+    # using direct HEVC stream URL for HTMLMediaElement/<video> playback,
+    # src/third_party/ffmpeg needs to be configured and built with
+    # --enable-demuxer=hevc and --enable-parser=hevc, see
+    # third_party/ffmpeg/chromium/scripts/build_ffmpeg.py
+    'enable_hevc_demuxing%': 0,
+
     # Support ChromeOS touchpad gestures with ozone.
     'use_evdev_gestures%': 0,
 
@@ -1806,6 +1814,7 @@
         'use_system_fontconfig%': 1,
       }],
       ['chromecast==1', {
+        'enable_hevc_demuxing%': 1,
         'enable_mpeg2ts_stream_parser%': 1,
         'ffmpeg_branding%': 'ChromeOS',
         'ozone_platform_ozonex%': 1,
@@ -2651,6 +2660,9 @@
           ['enable_mpeg2ts_stream_parser==1', {
             'defines': ['ENABLE_MPEG2TS_STREAM_PARSER'],
           }],
+          ['enable_hevc_demuxing==1', {
+            'defines': ['ENABLE_HEVC_DEMUXING'],
+          }],
         ],
       }],
       ['enable_viewport==1', {