Always compile VP9 source files.

Instead of optionally compile VP9 source files based on the value of
the GN argument 'rtc_libvpx_build_vp9', this CL uses the preprocessor
macro RTC_ENABLE_VP9 to decide if VP9 related code needs to be compiled
or not.

Bug: None
Change-Id: I5c1b69d7ec35e8446181d98c912277d0ae8fdba2
Reviewed-on: https://webrtc-review.googlesource.com/c/111063
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25685}
diff --git a/modules/video_coding/codecs/vp9/vp9_impl.cc b/modules/video_coding/codecs/vp9/vp9_impl.cc
index 7dea25f..a19316c 100644
--- a/modules/video_coding/codecs/vp9/vp9_impl.cc
+++ b/modules/video_coding/codecs/vp9/vp9_impl.cc
@@ -9,6 +9,8 @@
  *
  */
 
+#ifdef RTC_ENABLE_VP9
+
 #include "modules/video_coding/codecs/vp9/vp9_impl.h"
 
 #include <algorithm>
@@ -124,23 +126,6 @@
 }
 }  // namespace
 
-std::vector<SdpVideoFormat> SupportedVP9Codecs() {
-  // TODO(emircan): Add Profile 2 support after fixing browser_tests.
-  std::vector<SdpVideoFormat> supported_formats{SdpVideoFormat(
-      cricket::kVp9CodecName,
-      {{kVP9FmtpProfileId, VP9ProfileToString(VP9Profile::kProfile0)}})};
-  return supported_formats;
-}
-
-std::unique_ptr<VP9Encoder> VP9Encoder::Create() {
-  return absl::make_unique<VP9EncoderImpl>(cricket::VideoCodec());
-}
-
-std::unique_ptr<VP9Encoder> VP9Encoder::Create(
-    const cricket::VideoCodec& codec) {
-  return absl::make_unique<VP9EncoderImpl>(codec);
-}
-
 void VP9EncoderImpl::EncoderOutputCodedPacketCallback(vpx_codec_cx_pkt* pkt,
                                                       void* user_data) {
   VP9EncoderImpl* enc = static_cast<VP9EncoderImpl*>(user_data);
@@ -1260,10 +1245,6 @@
   return info;
 }
 
-std::unique_ptr<VP9Decoder> VP9Decoder::Create() {
-  return absl::make_unique<VP9DecoderImpl>();
-}
-
 VP9DecoderImpl::VP9DecoderImpl()
     : decode_complete_callback_(nullptr),
       inited_(false),
@@ -1458,3 +1439,5 @@
 }
 
 }  // namespace webrtc
+
+#endif  // RTC_ENABLE_VP9