Cast: Re-factor rtcp_sender.cc into rtcp_builder.cc and do some cleanup

media/cast/cast_testing.gypi

 # Copyright 2014 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.
 
 {
   'targets': [
     {
       # GN version: //media/cast:test_support
       'target_name': 'cast_test_utility',
       'type': 'static_library',
@@ skipping 68 matching lines @@
         'logging/logging_impl_unittest.cc',
         'logging/logging_raw_unittest.cc',
         'logging/receiver_time_offset_estimator_impl_unittest.cc',
         'logging/simple_event_subscriber_unittest.cc',
         'logging/stats_event_subscriber_unittest.cc',
         'net/cast_transport_sender_impl_unittest.cc',
         'net/frame_id_wrap_helper_test.cc',
         'net/pacing/mock_paced_packet_sender.cc',
         'net/pacing/mock_paced_packet_sender.h',
         'net/pacing/paced_sender_unittest.cc',
-        'net/rtcp/rtcp_sender_unittest.cc',
+        'net/rtcp/rtcp_builder_unittest.cc',
         'net/rtcp/rtcp_unittest.cc',
         'net/rtcp/rtcp_utility_unittest.cc',
         'net/rtcp/receiver_rtcp_event_subscriber_unittest.cc',
 # TODO(miu): The following two are test utility modules.  Rename/move the files.
         'net/rtcp/test_rtcp_packet_builder.cc',
         'net/rtcp/test_rtcp_packet_builder.h',
         'net/rtp/cast_message_builder_unittest.cc',
         'net/rtp/frame_buffer_unittest.cc',
         'net/rtp/framer_unittest.cc',
         'net/rtp/mock_rtp_payload_feedback.cc',
@@ skipping 236 matching lines @@
             ],
             'sources': [
               'test/utility/tap_proxy.cc',
             ],
           }
         ]
       }
     ]
   ], # targets
 }