Introduce NullVideoSink for test classes.

media/base/BUILD.gn

 # 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.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//media/media_options.gni")
@@ skipping 103 matching lines @@
     "media_keys.h",
     "media_log.cc",
     "media_log.h",
     "media_log_event.h",
     "media_permission.cc",
     "media_permission.h",
     "media_switches.cc",
     "media_switches.h",
     "multi_channel_resampler.cc",
     "multi_channel_resampler.h",
+    "null_video_sink.cc",
+    "null_video_sink.h",
     "pipeline.cc",
     "pipeline.h",
     "pipeline_status.h",
     "player_tracker.cc",
     "player_tracker.h",
     "ranges.cc",
     "ranges.h",
     "renderer.cc",
     "renderer.h",
     "renderer_factory.cc",
@@ skipping 233 matching lines @@
     "callback_holder_unittest.cc",
     "channel_mixer_unittest.cc",
     "channel_mixing_matrix_unittest.cc",
     "data_buffer_unittest.cc",
     "decoder_buffer_queue_unittest.cc",
     "decoder_buffer_unittest.cc",
     "djb2_unittest.cc",
     "gmock_callback_support_unittest.cc",
     "key_systems_unittest.cc",
     "multi_channel_resampler_unittest.cc",
+    "null_video_sink_unittest.cc",
     "pipeline_unittest.cc",
     "ranges_unittest.cc",
     "run_all_unittests.cc",
     "seekable_buffer_unittest.cc",
     "serial_runner_unittest.cc",
     "sinc_resampler_unittest.cc",
     "stream_parser_unittest.cc",
     "text_ranges_unittest.cc",
     "text_renderer_unittest.cc",
     "user_input_monitor_unittest.cc",
@@ skipping 132 matching lines @@
       if (is_posix) {
         yasm_flags += [ "-DELF" ]
         if (current_cpu == "x64") {
           # TODO(ajwong): Why isn't this true in mac?
           yasm_flags += [ "-DPIC" ]
         }
       }
     }
   }
 }