media/gpu/v4l2svd: use legacy H.264 decoder

The "new" H.264 decoder is designed to be used with a kernel that
supports request API and the upstream H.264 definitions. However the
V4L2SVD still does not support requests and only works on older kernels,
so make sure to select the legacy decoder for now.

Bug: 987856
Test: video_decode_accelerator_tests with --use_vd on Kevin.
Change-Id: Iccad414633395574b9a74f8e77c96f9ccdf3a223
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761947
Commit-Queue: Alexandre Courbot <acourbot@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Auto-Submit: Alexandre Courbot <acourbot@chromium.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688438}

media/gpu/v4l2/v4l2_slice_video_decoder.cc

@@ -17,7 +17,7 @@
 #include "media/gpu/gpu_video_decode_accelerator_helpers.h"
 #include "media/gpu/linux/dmabuf_video_frame_pool.h"
 #include "media/gpu/macros.h"
-#include "media/gpu/v4l2/v4l2_h264_accelerator.h"
+#include "media/gpu/v4l2/v4l2_h264_accelerator_legacy.h"
 #include "media/gpu/v4l2/v4l2_vp8_accelerator.h"
 #include "media/gpu/v4l2/v4l2_vp9_accelerator.h"
 
@@ -345,7 +345,7 @@ void V4L2SliceVideoDecoder::InitializeTask(const VideoDecoderConfig& config,
   // TODO(akahuang): Check the profile is supported.
   if (profile >= H264PROFILE_MIN && profile <= H264PROFILE_MAX) {
     avd_.reset(new H264Decoder(
-        std::make_unique<V4L2H264Accelerator>(this, device_.get())));
+        std::make_unique<V4L2LegacyH264Accelerator>(this, device_.get())));
   } else if (profile >= VP8PROFILE_MIN && profile <= VP8PROFILE_MAX) {
     avd_.reset(new VP8Decoder(
         std::make_unique<V4L2VP8Accelerator>(this, device_.get())));