vpx_video_decoder: enable VP9D_SET_LOOP_FILTER_OPT

this improves performance by ~10% on 1080P clips

Bug: 1076203
Change-Id: I68e1d35b9cc3550024d63003206939456f273898
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2233491
Commit-Queue: James Zern <jzern@google.com>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775865}

media/filters/vpx_video_decoder.cc

@@ -242,6 +242,14 @@ bool VpxVideoDecoder::ConfigureDecoder(const VideoDecoderConfig& config) {
                   << vpx_codec_error(vpx_codec_.get());
       return false;
     }
+
+    vpx_codec_err_t status =
+        vpx_codec_control(vpx_codec_.get(), VP9D_SET_LOOP_FILTER_OPT, 1);
+    if (status != VPX_CODEC_OK) {
+      DLOG(ERROR) << "Failed to enable VP9D_SET_LOOP_FILTER_OPT. "
+                  << vpx_codec_error(vpx_codec_.get());
+      return false;
+    }
   }
 
   if (config.alpha_mode() == VideoDecoderConfig::AlphaMode::kIsOpaque)