[chrome.displaySource] Add a base class for audio and video encoders.

extensions/renderer/api/display_source/wifi_display/wifi_display_media_pipeline.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/api/display_source/wifi_display/wifi_display_media_pipeline.h"
 
 #include "base/logging.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/video_encode_accelerator.h"
 #include "extensions/renderer/api/display_source/wifi_display/wifi_display_elementary_stream_descriptor.h"
@@ skipping 144 matching lines @@
   DCHECK(media_service_);
   auto error_callback = base::Bind(error_callback_, kErrorUnableSendMedia);
   media_service_.set_connection_error_handler(error_callback);
   media_service_->SetDesinationPoint(
       sink_ip_address_,
       static_cast<int32_t>(sink_rtp_ports_.first),
       init_completion_callback_);
 }
 
 void WiFiDisplayMediaPipeline::OnEncodedVideoFrame(
-    const WiFiDisplayEncodedFrame& frame) {
+    std::unique_ptr<WiFiDisplayEncodedFrame> frame) {
   DCHECK(packetizer_);
-  if (!packetizer_->EncodeElementaryStreamUnit(
-      0u, frame.bytes(), frame.data.size(), frame.key_frame, frame.pts,
-          frame.dts, true)) {
+  if (!packetizer_->EncodeElementaryStreamUnit(0u, frame->bytes(),
+                                               frame->size(), frame->key_frame,
+                                               frame->pts, frame->dts, true)) {
     DVLOG(1) << "Couldn't write video mpegts packet";
   }
 }
 
 bool WiFiDisplayMediaPipeline::OnPacketizedMediaDatagramPacket(
     WiFiDisplayMediaDatagramPacket media_datagram_packet) {
   DCHECK(media_service_);
   media_service_->SendMediaPacket(std::move(media_datagram_packet));
   return true;
 }
 
 }  // namespace extensions