Media Galleries API Metadata: Add audio video metadata extractor.

media/media.gyp

Index: media/media.gyp
diff --git a/media/media.gyp b/media/media.gyp
index 9aaba42f484f2122e261d59a076f4adc84097cac..472b9cda2476d579754044e8961a28c78c367773 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -239,6 +239,8 @@
         'base/audio_splicer.h',
         'base/audio_timestamp_helper.cc',
         'base/audio_timestamp_helper.h',
+        'base/audio_video_metadata_extractor.cc',
+        'base/audio_video_metadata_extractor.h',
         'base/bind_to_loop.h',
         'base/bit_reader.cc',
         'base/bit_reader.h',
@@ -508,6 +510,8 @@
         }, {  # media_use_ffmpeg==0
           # Exclude the sources that depend on ffmpeg.
           'sources!': [
+            'base/audio_video_metadata_extractor.cc',
+            'base/audio_video_metadata_extractor.h',
             'base/container_names.cc',
             'base/container_names.h',
             'base/media_file_checker.cc',
@@ -940,6 +944,7 @@
         'base/audio_renderer_mixer_unittest.cc',
         'base/audio_splicer_unittest.cc',
         'base/audio_timestamp_helper_unittest.cc',
+        'base/audio_video_metadata_extractor_unittest.cc',
         'base/bind_to_loop_unittest.cc',
         'base/bit_reader_unittest.cc',
         'base/callback_holder.h',
@@ -1028,6 +1033,7 @@
           ],
         }, {  # media_use_ffmpeg== 0
           'sources!': [
+            'base/audio_video_metadata_extractor_unittest.cc',
             'base/media_file_checker_unittest.cc',
           ],
         }],