Don't use VP9 specific concepts to combine spatial layer frames in FrameBuffer2.

The Dependency Descriptor use unique ids for every frame, meaning spatial layer frames will all have unique ids.

Bug: webrtc:10342
Change-Id: I241a8b3959e27bd918ae7a907ab5158fe9dcd7a5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/194327
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32655}
diff --git a/video/rtp_video_stream_receiver2_unittest.cc b/video/rtp_video_stream_receiver2_unittest.cc
index 7d69063..dabd9ff 100644
--- a/video/rtp_video_stream_receiver2_unittest.cc
+++ b/video/rtp_video_stream_receiver2_unittest.cc
@@ -870,7 +870,7 @@
         EXPECT_EQ(frame->num_references, 2U);
         EXPECT_EQ(frame->references[0], frame->id.picture_id - 90);
         EXPECT_EQ(frame->references[1], frame->id.picture_id - 80);
-        EXPECT_EQ(frame->id.spatial_layer, kSpatialIndex);
+        EXPECT_EQ(frame->SpatialIndex(), kSpatialIndex);
         EXPECT_THAT(frame->PacketInfos(), SizeIs(1));
       }));
 
@@ -926,7 +926,7 @@
   EXPECT_CALL(mock_on_complete_frame_callback_, DoOnCompleteFrame)
       .WillOnce(Invoke([kSpatialIndex](video_coding::EncodedFrame* frame) {
         EXPECT_EQ(frame->num_references, 0U);
-        EXPECT_EQ(frame->id.spatial_layer, kSpatialIndex);
+        EXPECT_EQ(frame->SpatialIndex(), kSpatialIndex);
         EXPECT_EQ(frame->EncodedImage()._encodedWidth, 480u);
         EXPECT_EQ(frame->EncodedImage()._encodedHeight, 360u);
         EXPECT_THAT(frame->PacketInfos(), SizeIs(2));