[chrome.displaySource] Move mojo interfaces to a nested namespace.

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"
 
@@ skipping 217 matching lines @@
   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_);
-  WiFiDisplayMediaPacketPtr packet = WiFiDisplayMediaPacket::New();
+  mojom::WiFiDisplayMediaPacketPtr packet =
+      mojom::WiFiDisplayMediaPacket::New();
   packet->data = std::move(media_datagram_packet);
   media_service_->SendMediaPacket(std::move(packet));
   return true;
 }
 
 }  // namespace extensions