Fix disabling FFMpeg video decoders on non-Android platforms

If disable_ffmpeg_video_decoders is set to true on platfoms other
than Android ffmped_video_decoder.* is always included.
This patch removes those sources and fixes dependencies in code.

Review-Url: https://codereview.chromium.org/2808093008
Cr-Commit-Position: refs/heads/master@{#464394}

content/browser/media/media_internals.cc

@@ -29,7 +29,7 @@
 #include "media/base/media_log_event.h"
 #include "media/filters/gpu_video_decoder.h"
 
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
 #include "media/filters/decrypting_video_decoder.h"
 #endif
 
@@ -487,7 +487,7 @@ std::string MediaInternals::MediaInternalsUMAHandler::GetUMANameForAVStream(
     return uma_name + "Other";
   }
 
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
   if (player_info.video_decoder ==
       media::DecryptingVideoDecoder::kDecoderName) {
     return uma_name + "DVD";

media/BUILD.gn

@@ -324,11 +324,15 @@ component("media") {
       "filters/ffmpeg_demuxer.cc",
       "filters/ffmpeg_demuxer.h",
       "filters/ffmpeg_glue.cc",
-      "filters/ffmpeg_video_decoder.cc",
-      "filters/ffmpeg_video_decoder.h",
       "filters/in_memory_url_protocol.cc",
       "filters/in_memory_url_protocol.h",
     ]
+    if (!disable_ffmpeg_video_decoders) {
+      sources += [
+        "filters/ffmpeg_video_decoder.cc",
+        "filters/ffmpeg_video_decoder.h",
+      ]
+    }
     if (proprietary_codecs) {
       sources += [
         "filters/ffmpeg_aac_bitstream_converter.cc",
@@ -372,24 +376,21 @@ component("media") {
     deps += [ "//third_party/libvpx" ]
   }
 
-  if (is_android) {
-    # On Android, FFmpeg is built without video decoders. We only
-    # support hardware video decoding.
-    if (disable_ffmpeg_video_decoders) {
+  if (disable_ffmpeg_video_decoders) {
       sources -= [
-        "filters/ffmpeg_video_decoder.cc",
-        "filters/ffmpeg_video_decoder.h",
+        "filters/decrypting_video_decoder.cc",
+        "filters/decrypting_video_decoder.h",
       ]
-    }
-    sources += [
-      "filters/android/media_codec_audio_decoder.cc",
-      "filters/android/media_codec_audio_decoder.h",
-    ]
+  }
+
+  if (is_android) {
     sources -= [
       "filters/decrypting_audio_decoder.cc",
       "filters/decrypting_audio_decoder.h",
-      "filters/decrypting_video_decoder.cc",
-      "filters/decrypting_video_decoder.h",
+    ]
+    sources += [
+      "filters/android/media_codec_audio_decoder.cc",
+      "filters/android/media_codec_audio_decoder.h",
     ]
   }
 
@@ -624,7 +625,7 @@ source_set("unit_tests") {
 
   data_deps = []
 
-  if (is_android) {
+  if (disable_ffmpeg_video_decoders) {
     sources -= [
       "filters/decrypting_audio_decoder_unittest.cc",
       "filters/decrypting_video_decoder_unittest.cc",
@@ -657,9 +658,8 @@ source_set("unit_tests") {
       "//third_party/opus",
     ]
 
-    if (!is_android) {
+    if (!disable_ffmpeg_video_decoders) {
       sources += [
-        # FFmpeg on Android does not include video decoders.
         "filters/ffmpeg_video_decoder_unittest.cc",
       ]
     }

media/filters/decoder_selector.cc

@@ -20,7 +20,7 @@
 #include "media/filters/decoder_stream_traits.h"
 #include "media/filters/decrypting_demuxer_stream.h"
 
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
 #include "media/filters/decrypting_audio_decoder.h"
 #include "media/filters/decrypting_video_decoder.h"
 #endif
@@ -96,7 +96,7 @@ void DecoderSelector<StreamType>::SelectDecoder(
   // When there is a CDM attached, always try the decrypting decoder or
   // demuxer-stream first.
   if (cdm_context_) {
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
     InitializeDecryptingDecoder();
 #else
     InitializeDecryptingDemuxerStream();
@@ -112,7 +112,7 @@ void DecoderSelector<StreamType>::SelectDecoder(
   InitializeDecoder();
 }
 
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
 template <DemuxerStream::Type StreamType>
 void DecoderSelector<StreamType>::InitializeDecryptingDecoder() {
   DVLOG(2) << __func__;
@@ -145,7 +145,7 @@ void DecoderSelector<StreamType>::DecryptingDecoderInitDone(bool success) {
   // DecryptingDemuxerStream to do decrypt-only.
   InitializeDecryptingDemuxerStream();
 }
-#endif  // !defined(OS_ANDROID)
+#endif  // !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
 
 template <DemuxerStream::Type StreamType>
 void DecoderSelector<StreamType>::InitializeDecryptingDemuxerStream() {