[rtp_rtcp] fixed namespaces lint warnings

webrtc/modules/rtp_rtcp/source/rtcp_format_remb_unittest.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 #include "webrtc/common_types.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/mock/mock_remote_bitrate_observer.h"
 #include "webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_receiver.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_sender.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 #include "webrtc/test/null_transport.h"
 #include "webrtc/typedefs.h"
 
+namespace webrtc {
 namespace {
 
-using namespace webrtc;
-
 class TestTransport : public Transport {
  public:
   TestTransport(RTCPReceiver* rtcp_receiver) : rtcp_receiver_(rtcp_receiver) {}
 
   bool SendRtp(const uint8_t* /*data*/,
                size_t /*len*/,
                const PacketOptions& options) override {
     return false;
   }
   bool SendRtcp(const uint8_t* packet, size_t packetLength) override {
@@ skipping 85 matching lines @@
 
 TEST_F(RtcpFormatRembTest, TestCompund) {
   uint32_t SSRCs[2] = {456789, 98765};
   rtcp_sender_->SetRTCPStatus(RtcpMode::kCompound);
   rtcp_sender_->SetREMBData(1234, std::vector<uint32_t>(SSRCs, SSRCs + 2));
   RTCPSender::FeedbackState feedback_state =
       dummy_rtp_rtcp_impl_->GetFeedbackState();
   EXPECT_EQ(0, rtcp_sender_->SendRTCP(feedback_state, kRtcpRemb));
 }
 }  // namespace
+}  // namespace webrtc