Convert USE_PROPRIETARY_CODECS to a buildflag header.

media/base/mime_util_unittest.cc

Index: media/base/mime_util_unittest.cc
diff --git a/media/base/mime_util_unittest.cc b/media/base/mime_util_unittest.cc
index 10e4aec1194175521bab7d9e8a9346a1ee5ecc66..8d630dc4c14f6b6bc9bf473cd18ae8c6cb16fe16 100644
--- a/media/base/mime_util_unittest.cc
+++ b/media/base/mime_util_unittest.cc
@@ -134,7 +134,7 @@ TEST(MimeUtilTest, CommonMediaMimeType) {
   EXPECT_TRUE(IsSupportedMediaMimeType("video/ogg"));
 #endif  // OS_ANDROID
 
-#if defined(OS_ANDROID) && defined(USE_PROPRIETARY_CODECS)
+#if defined(OS_ANDROID) && BUILDFLAG(USE_PROPRIETARY_CODECS)
   // HLS is supported on Android API level 14 and higher and Chrome supports
   // API levels 15 and higher, so these are expected to be supported.
   bool kHlsSupported = true;
@@ -149,7 +149,7 @@ TEST(MimeUtilTest, CommonMediaMimeType) {
   EXPECT_EQ(kHlsSupported, IsSupportedMediaMimeType("audio/mpegurl"));
   EXPECT_EQ(kHlsSupported, IsSupportedMediaMimeType("audio/x-mpegurl"));
 
-#if defined(USE_PROPRIETARY_CODECS)
+#if BUILDFLAG(USE_PROPRIETARY_CODECS)
   EXPECT_TRUE(IsSupportedMediaMimeType("audio/mp4"));
   EXPECT_TRUE(IsSupportedMediaMimeType("audio/x-m4a"));
   EXPECT_TRUE(IsSupportedMediaMimeType("video/mp4"));