Re-land "Convert native handles to buffers before encoding."

webrtc/common_video/i420_buffer_pool.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 22 matching lines @@
   uint8_t* data(webrtc::PlaneType type) {
     DCHECK(HasOneRef());
     const webrtc::I420Buffer* cbuffer = buffer_.get();
     return const_cast<uint8_t*>(cbuffer->data(type));
   }
   int stride(webrtc::PlaneType type) const override {
     return buffer_->stride(type);
   }
   void* native_handle() const override { return nullptr; }
 
+  rtc::scoped_refptr<VideoFrameBuffer> NativeToI420Buffer() override {
+    RTC_NOTREACHED();
+    return nullptr;
+  }
+
   friend class rtc::RefCountedObject<PooledI420Buffer>;
   rtc::scoped_refptr<webrtc::I420Buffer> buffer_;
 };
 
 }  // namespace
 
 namespace webrtc {
 
 I420BufferPool::I420BufferPool() {
   Release();
@@ skipping 23 matching lines @@
     // and it's safe to reuse.
     if (buffer->HasOneRef())
       return new rtc::RefCountedObject<PooledI420Buffer>(buffer);
   }
   // Allocate new buffer.
   buffers_.push_back(new rtc::RefCountedObject<I420Buffer>(width, height));
   return new rtc::RefCountedObject<PooledI420Buffer>(buffers_.back());
 }
 
 }  // namespace webrtc