Convert USE_PROPRIETARY_CODECS to a buildflag header.

media/base/audio_video_metadata_extractor_unittest.cc

Index: media/base/audio_video_metadata_extractor_unittest.cc
diff --git a/media/base/audio_video_metadata_extractor_unittest.cc b/media/base/audio_video_metadata_extractor_unittest.cc
index a9cc5eca1887e07ddbdb9d6cf7acc108fbb772eb..084e0ededd5c159fcd5352973d3a031d74594227 100644
--- a/media/base/audio_video_metadata_extractor_unittest.cc
+++ b/media/base/audio_video_metadata_extractor_unittest.cc
@@ -11,6 +11,7 @@
 #include "build/build_config.h"
 #include "media/base/test_data_util.h"
 #include "media/filters/file_data_source.h"
+#include "media/media_features.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
@@ -123,7 +124,7 @@ TEST(AudioVideoMetadataExtractorTest, VideoWebM) {
   EXPECT_EQ(0u, extractor->attached_images_bytes().size());
 }
 
-#if defined(USE_PROPRIETARY_CODECS)
+#if BUILDFLAG(USE_PROPRIETARY_CODECS)
 TEST(AudioVideoMetadataExtractorTest, AndroidRotatedMP4Video) {
   std::unique_ptr<AudioVideoMetadataExtractor> extractor =
       GetExtractor("90rotation.mp4", true, true, 0, 1920, 1080);