Move MockFFmpeg instance setting into the constructor/destructor.

media/media.gyp

Index: media/media.gyp
===================================================================
--- media/media.gyp	(revision 75179)
+++ media/media.gyp	(working copy)
@@ -399,53 +399,6 @@
             }],
           ],
         }],
-        # media_unittests is failing like crazy on Windows. So disable all test
-        # cases. See bug: http://crbug.com/72790
-        ['OS=="win"', {
-          'sources!': [
-            'audio/audio_input_controller_unittest.cc',
-            'audio/audio_input_unittest.cc',
-            'audio/audio_output_controller_unittest.cc',
-            'audio/audio_output_proxy_unittest.cc',
-            'audio/audio_parameters_unittest.cc',
-            'audio/audio_util_unittest.cc',
-            'audio/fake_audio_input_stream_unittest.cc',
-            'audio/linux/alsa_output_unittest.cc',
-            'audio/mac/audio_output_mac_unittest.cc',
-            'audio/simple_sources_unittest.cc',
-            'audio/win/audio_output_win_unittest.cc',
-            'base/composite_filter_unittest.cc',
-            'base/clock_impl_unittest.cc',
-            'base/data_buffer_unittest.cc',
-            'base/djb2_unittest.cc',
-            'base/filter_collection_unittest.cc',
-            'base/h264_bitstream_converter_unittest.cc',
-            'base/mock_ffmpeg.cc',
-            'base/mock_ffmpeg.h',
-            'base/mock_reader.h',
-            'base/mock_task.cc',
-            'base/mock_task.h',
-            'base/pipeline_impl_unittest.cc',
-            'base/pts_heap_unittest.cc',
-            'base/seekable_buffer_unittest.cc',
-            'base/state_matrix_unittest.cc',
-            'base/video_frame_unittest.cc',
-            'base/yuv_convert_unittest.cc',
-            'filters/audio_renderer_algorithm_ola_unittest.cc',
-            'filters/audio_renderer_base_unittest.cc',
-            'filters/bitstream_converter_unittest.cc',
-            'filters/decoder_base_unittest.cc',
-            'filters/ffmpeg_demuxer_unittest.cc',
-            'filters/ffmpeg_glue_unittest.cc',
-            'filters/ffmpeg_h264_bitstream_converter_unittest.cc',
-            'filters/ffmpeg_video_decoder_unittest.cc',
-            'filters/file_data_source_unittest.cc',
-            'filters/video_renderer_base_unittest.cc',
-            'omx/mock_omx.cc',
-            'omx/mock_omx.h',
-            'video/ffmpeg_video_decode_engine_unittest.cc',
-          ],
-        }],
       ],
     },
     {