fix build when ffmpeg, libvpx and libwebm are disabled

content/renderer/pepper/video_decoder_shim.cc

Index: content/renderer/pepper/video_decoder_shim.cc
diff --git a/content/renderer/pepper/video_decoder_shim.cc b/content/renderer/pepper/video_decoder_shim.cc
index 3f2c5e807e02f02517f6975ae9012bb17a5661a0..791c6e629b31a4ff7b846647e5e9041c9de95b6c 100644
--- a/content/renderer/pepper/video_decoder_shim.cc
+++ b/content/renderer/pepper/video_decoder_shim.cc
@@ -48,7 +48,11 @@ bool IsCodecSupported(media::VideoCodec codec) {
     return true;
 #endif
 
+#if !defined(MEDIA_DISABLE_FFMPEG) && !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
   return media::FFmpegVideoDecoder::IsCodecSupported(codec);
+#else
+  return false;
+#endif
 }
 
 }  // namespace
@@ -688,12 +692,18 @@ void VideoDecoderShim::DecoderImpl::Initialize(
         new media::VpxVideoDecoder(base::ThreadTaskRunnerHandle::Get()));
   } else
 #endif
+
+#if !defined(MEDIA_DISABLE_FFMPEG) && !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
   {
     scoped_ptr<media::FFmpegVideoDecoder> ffmpeg_video_decoder(
         new media::FFmpegVideoDecoder(base::ThreadTaskRunnerHandle::Get()));
     ffmpeg_video_decoder->set_decode_nalus(true);
     decoder_ = ffmpeg_video_decoder.Pass();
   }
+#elif defined(MEDIA_DISABLE_LIBVPX)
+  OnInitDone(false);
+  return;
+#endif
 
   // VpxVideoDecoder and FFmpegVideoDecoder support only one pending Decode()
   // request.