Change the media::PowerLineFrequency from an enum class to a proper class

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 391 matching lines @@
     "seekable_buffer_unittest.cc",
     "serial_runner_unittest.cc",
     "sinc_resampler_unittest.cc",
     "stream_parser_unittest.cc",
     "text_ranges_unittest.cc",
     "text_renderer_unittest.cc",
     "time_delta_interpolator_unittest.cc",
     "user_input_monitor_unittest.cc",
     "vector_math_testing.h",
     "vector_math_unittest.cc",
+    "video_capture_types_unittest.cc",
     "video_frame_pool_unittest.cc",
     "video_frame_unittest.cc",
     "video_util_unittest.cc",
     "wall_clock_time_source_unittest.cc",
     "yuv_convert_unittest.cc",
   ]
   configs += [
     "//build/config/compiler:no_size_t_to_int_warning",
     "//media:media_config",
   ]
@@ skipping 105 matching lines @@
       if (is_posix) {
         yasm_flags += [ "-DELF" ]
         if (current_cpu == "x64") {
           # TODO(ajwong): Why isn't this true in mac?
           yasm_flags += [ "-DPIC" ]
         }
       }
     }
   }
 }