Reland "Remove RTPVideoHeader::vp8() accessors."

This reverts commit 1811c04f22a26da3ed2832373a5c92a9786420c3.

Reason for revert: Downstream projects fixed.

Original change's description:
> Revert "Remove RTPVideoHeader::vp8() accessors."
> 
> This reverts commit af7afc66427b0e9109e7d492f2805d63d239b914.
> 
> Reason for revert: Break downstream projects.
> 
> Original change's description:
> > Remove RTPVideoHeader::vp8() accessors.
> > 
> > Bug: none
> > Change-Id: Ia7d65148fb36a8f26647bee8a876ce7217ff8a68
> > Reviewed-on: https://webrtc-review.googlesource.com/93321
> > Reviewed-by: Niels Moller <nisse@webrtc.org>
> > Reviewed-by: Stefan Holmer <stefan@webrtc.org>
> > Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
> > Commit-Queue: Philip Eliasson <philipel@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#24626}
> 
> TBR=danilchap@webrtc.org,nisse@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,philipel@webrtc.org,holmer@google.com
> 
> Change-Id: I3f7f19c0ea810c0fd988c59e6556bbea9b756b33
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: none
> Reviewed-on: https://webrtc-review.googlesource.com/98864
> Reviewed-by: Philip Eliasson <philipel@webrtc.org>
> Commit-Queue: Philip Eliasson <philipel@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#24628}

TBR=danilchap@webrtc.org,nisse@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,philipel@webrtc.org,holmer@google.com

Change-Id: I9246f36e638108ae4fc46c1ae4559c8205d50fc1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: none
Reviewed-on: https://webrtc-review.googlesource.com/98841
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24629}
diff --git a/test/configurable_frame_size_encoder.cc b/test/configurable_frame_size_encoder.cc
index c18c938..c0fe296 100644
--- a/test/configurable_frame_size_encoder.cc
+++ b/test/configurable_frame_size_encoder.cc
@@ -24,7 +24,8 @@
     : callback_(NULL),
       max_frame_size_(max_frame_size),
       current_frame_size_(max_frame_size),
-      buffer_(new uint8_t[max_frame_size]) {
+      buffer_(new uint8_t[max_frame_size]),
+      codec_type_(kVideoCodecGeneric) {
   memset(buffer_.get(), 0, max_frame_size);
 }
 
@@ -50,8 +51,8 @@
   encodedImage.SetTimestamp(inputImage.timestamp());
   encodedImage.capture_time_ms_ = inputImage.render_time_ms();
   RTPFragmentationHeader* fragmentation = NULL;
-  CodecSpecificInfo specific;
-  memset(&specific, 0, sizeof(specific));
+  CodecSpecificInfo specific{};
+  specific.codecType = codec_type_;
   callback_->OnEncodedImage(encodedImage, &specific, fragmentation);
 
   return WEBRTC_VIDEO_CODEC_OK;
@@ -84,5 +85,9 @@
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+void ConfigurableFrameSizeEncoder::SetCodecType(VideoCodecType codec_type) {
+  codec_type_ = codec_type;
+}
+
 }  // namespace test
 }  // namespace webrtc