Fix build with ffmpeg-4.x

Obtained from:
https://git.archlinux.org/svntogit/packages.git/tree/trunk/qtwebengine-ffmpeg4.patch?h=packages/qt5-webengine&id=421103a8798335f7788498e56b5eef3f33ecba26

--- src/3rdparty/chromium/media/base/decoder_buffer.h.orig	2018-01-15 11:39:43 UTC
+++ src/3rdparty/chromium/media/base/decoder_buffer.h
@@ -37,7 +37,7 @@ class MEDIA_EXPORT DecoderBuffer
     : public base::RefCountedThreadSafe<DecoderBuffer> {
  public:
   enum {
-    kPaddingSize = 32,
+    kPaddingSize = 64,
 #if defined(ARCH_CPU_ARM_FAMILY)
     kAlignmentSize = 16
 #else
--- src/3rdparty/chromium/media/ffmpeg/ffmpeg_common.cc.orig	2018-01-15 11:39:43 UTC
+++ src/3rdparty/chromium/media/ffmpeg/ffmpeg_common.cc
@@ -30,10 +30,10 @@ EncryptionScheme GetEncryptionScheme(const AVStream* s
 
 }  // namespace
 
-// Why FF_INPUT_BUFFER_PADDING_SIZE? FFmpeg assumes all input buffers are
+// Why AV_INPUT_BUFFER_PADDING_SIZE? FFmpeg assumes all input buffers are
 // padded. Check here to ensure FFmpeg only receives data padded to its
 // specifications.
-static_assert(DecoderBuffer::kPaddingSize >= FF_INPUT_BUFFER_PADDING_SIZE,
+static_assert(DecoderBuffer::kPaddingSize >= AV_INPUT_BUFFER_PADDING_SIZE,
               "DecoderBuffer padding size does not fit ffmpeg requirement");
 
 // Alignment requirement by FFmpeg for input and output buffers. This need to
@@ -429,11 +429,11 @@ void AudioDecoderConfigToAVCodecContext(const AudioDec
   } else {
     codec_context->extradata_size = config.extra_data().size();
     codec_context->extradata = reinterpret_cast<uint8_t*>(
-        av_malloc(config.extra_data().size() + FF_INPUT_BUFFER_PADDING_SIZE));
+        av_malloc(config.extra_data().size() + AV_INPUT_BUFFER_PADDING_SIZE));
     memcpy(codec_context->extradata, &config.extra_data()[0],
            config.extra_data().size());
     memset(codec_context->extradata + config.extra_data().size(), '\0',
-           FF_INPUT_BUFFER_PADDING_SIZE);
+           AV_INPUT_BUFFER_PADDING_SIZE);
   }
 }
 
@@ -561,11 +561,11 @@ void VideoDecoderConfigToAVCodecContext(
   } else {
     codec_context->extradata_size = config.extra_data().size();
     codec_context->extradata = reinterpret_cast<uint8_t*>(
-        av_malloc(config.extra_data().size() + FF_INPUT_BUFFER_PADDING_SIZE));
+        av_malloc(config.extra_data().size() + AV_INPUT_BUFFER_PADDING_SIZE));
     memcpy(codec_context->extradata, &config.extra_data()[0],
            config.extra_data().size());
     memset(codec_context->extradata + config.extra_data().size(), '\0',
-           FF_INPUT_BUFFER_PADDING_SIZE);
+           AV_INPUT_BUFFER_PADDING_SIZE);
   }
 }
 
--- src/3rdparty/chromium/media/filters/ffmpeg_audio_decoder.cc.orig	2018-01-15 11:39:43 UTC
+++ src/3rdparty/chromium/media/filters/ffmpeg_audio_decoder.cc
@@ -53,7 +53,7 @@ static void ReleaseAudioBufferImpl(void* opaque, uint8
 // AVCodecContext.opaque to get the object reference in order to call
 // GetAudioBuffer() to do the actual allocation.
 static int GetAudioBuffer(struct AVCodecContext* s, AVFrame* frame, int flags) {
-  DCHECK(s->codec->capabilities & CODEC_CAP_DR1);
+  DCHECK(s->codec->capabilities & AV_CODEC_CAP_DR1);
   DCHECK_EQ(s->codec_type, AVMEDIA_TYPE_AUDIO);
 
   // Since this routine is called by FFmpeg when a buffer is required for audio
--- src/3rdparty/chromium/media/filters/ffmpeg_video_decoder.cc.orig	2018-01-15 11:39:43 UTC
+++ src/3rdparty/chromium/media/filters/ffmpeg_video_decoder.cc
@@ -415,12 +415,11 @@ bool FFmpegVideoDecoder::ConfigureDecoder(bool low_del
   codec_context_->thread_type =
       FF_THREAD_SLICE | (low_delay ? 0 : FF_THREAD_FRAME);
   codec_context_->opaque = this;
-  codec_context_->flags |= CODEC_FLAG_EMU_EDGE;
   codec_context_->get_buffer2 = GetVideoBufferImpl;
   codec_context_->refcounted_frames = 1;
 
   if (decode_nalus_)
-    codec_context_->flags2 |= CODEC_FLAG2_CHUNKS;
+    codec_context_->flags2 |= AV_CODEC_FLAG2_CHUNKS;
 
   AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
   if (!codec || avcodec_open2(codec_context_.get(), codec, NULL) < 0) {