media/vp9_parser: extend frame_hdr with loop_filter and segmentation

Current implementation of vp9 parser keeps the
segmentation and loop_filter headers as members of the
the FrameContext. This patch is for extending the frame_hdr
to include a copy of segmentation and loop_filter so that
all uncompressed header parameters can be direcly accessible
from the frame_hdr. The main intention is to help the
components like VEA to depend only on frame_hdr to populate
all required parameters in the uncompressed header to va api.

Note: The segmentation and loop_filter associated with the
Vp9FrameContextManager is possessing the calculated values, not
just the parsed bitstream parameters. If the client has to
parse the compressed header (which is not required for h/w
accelerated decoder and encoder implementation),
segmentation and loop_filter in context get updated based on
the dequants([1] section 8.6.1) and loop_filter frame init process ([1] 8.8.1).
[1] https://tools.ietf.org/html/rfc6386

Bug=chromium:924786

Change-Id: I9f1cdcbc93fd3afb21be731dd8e0bd252b773231
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531024Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Matthew Wolenetz <wolenetz@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660319}

media/filters/vp9_parser.h

@@ -260,6 +260,10 @@ struct MEDIA_EXPORT Vp9FrameHeader {
   Vp9FrameContext initial_frame_context;
   // Current frame entropy context after header parsing.
   Vp9FrameContext frame_context;
+
+  // Segmentation and loop filter params from uncompressed header
+  Vp9SegmentationParams segmentation;
+  Vp9LoopFilterParams loop_filter;
 };
 
 // A parser for VP9 bitstream.

media/filters/vp9_uncompressed_header_parser.cc

@@ -1083,10 +1083,13 @@ bool Vp9UncompressedHeaderParser::Parse(const uint8_t* stream,
   }
 
   ReadLoopFilterParams();
+  // Update loop_filter in current_frame_hdr
+  fhdr->loop_filter = context_->loop_filter_;
   ReadQuantizationParams(&fhdr->quant_params);
   if (!ReadSegmentationParams())
     return false;
-
+  // Update segmentation in current_frame_hdr
+  fhdr->segmentation = context_->segmentation_;
   if (!ReadTileInfo(fhdr))
     return false;