Disable native input mode in RTCVideoEncoder

Temporarily disables native input mode in RTCVideoEncoder until the fake
video capture device support GpuMemoryBuffer buffers.

Bug: 1014209, 982201
Test: Verify that tast.webrtc.DecodeAccelUsedVP8 passes
Change-Id: I7a99de95008ed0163760f320db7cc14c50c19d3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862535Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Commit-Queue: Ricky Liang <jcliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705892}

third_party/blink/renderer/platform/peerconnection/rtc_video_encoder.cc

@@ -372,15 +372,8 @@ void RTCVideoEncoder::Impl::CreateAndInitializeVEA(
   media::VideoPixelFormat pixel_format = media::PIXEL_FORMAT_I420;
   auto storage_type =
       media::VideoEncodeAccelerator::Config::StorageType::kShmem;
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kVideoCaptureUseGpuMemoryBuffer) &&
-      video_content_type_ != webrtc::VideoContentType::SCREENSHARE) {
-    // Use import mode for camera when GpuMemoryBuffer-based video capture is
-    // enabled.
-    pixel_format = media::PIXEL_FORMAT_NV12;
-    storage_type = media::VideoEncodeAccelerator::Config::StorageType::kDmabuf;
-    use_native_input_ = true;
-  }
+  // TODO(crbug.com/1014209): Enable native input mode after fake video capture
+  // device supports delivering GpuMemoryBuffer frames.
   const media::VideoEncodeAccelerator::Config config(
       pixel_format, input_visible_size_, profile, bitrate * 1000, base::nullopt,
       base::nullopt, base::nullopt, storage_type,