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

media/capture/video/mac/video_capture_device_mac.mm

 // Copyright (c) 2012 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.
 
 #include "media/capture/video/mac/video_capture_device_mac.h"
 
 #include <IOKit/IOCFPlugIn.h>
 #include <IOKit/usb/IOUSBLib.h>
 #include <IOKit/usb/USBSpec.h>
 
@@ skipping 398 matching lines @@
   // cameras are normally suspended so the configuration must happen right
   // before starting capture and during configuration.
   const std::string& device_model = device_name_.GetModel();
   if (device_model.length() > 2 * kVidPidSize) {
     std::string vendor_id = device_model.substr(0, kVidPidSize);
     std::string model_id = device_model.substr(kVidPidSize + 1);
     int vendor_id_as_int, model_id_as_int;
     if (base::HexStringToInt(base::StringPiece(vendor_id), &vendor_id_as_int) &&
         base::HexStringToInt(base::StringPiece(model_id), &model_id_as_int)) {
       SetAntiFlickerInUsbDevice(vendor_id_as_int, model_id_as_int,
-                                GetPowerLineFrequency(params));
+                                GetPowerLineFrequency(params).get());
     }
   }
 
   if (![capture_device_ startCapture]) {
     SetErrorState("Could not start capture device.");
     return;
   }
 
   state_ = kCapturing;
 }
@@ skipping 130 matching lines @@
   if (![capture_device_ setCaptureHeight:capture_format_.frame_size.height()
                                    width:capture_format_.frame_size.width()
                                frameRate:capture_format_.frame_rate]) {
     ReceiveError("Could not configure capture device.");
     return false;
   }
   return true;
 }
 
 }  // namespace media