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

media/base/video_capture_types.h

 // 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.
 
 #ifndef MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_
 #define MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_
 
 #include <vector>
 
 #include "build/build_config.h"
@@ skipping 37 matching lines @@
   // exceeding the maximum dimensions specified.
   RESOLUTION_POLICY_ANY_WITHIN_LIMIT,
 
   // Must always be equal to largest entry in the enum.
   RESOLUTION_POLICY_LAST = RESOLUTION_POLICY_ANY_WITHIN_LIMIT,
 };
 
 // Potential values of the googPowerLineFrequency optional constraint passed to
 // getUserMedia. Note that the numeric values are currently significant, and are
 // used to map enum values to corresponding frequency values.
-// TODO(ajose): http://crbug.com/525167 Consider making this a class.
-enum class PowerLineFrequency {
-  FREQUENCY_DEFAULT = 0,
-  FREQUENCY_50HZ = 50,
-  FREQUENCY_60HZ = 60,
-  FREQUENCY_MAX = FREQUENCY_60HZ
+class MEDIA_EXPORT PowerLineFrequency {
+private:

[wolenetz, 2015/09/09 19:39:15]

public before private:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Declaration_O...

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

+  int freq_;
+
+  void check(int freq);

[wolenetz, 2015/09/09 19:39:15]

methods before data members:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Declaration_O...

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

+public:
+  // Static members
+  static constexpr int FREQUENCY_DEFAULT = 0;

[wolenetz, 2015/09/09 19:39:15]

constexpr usage is currently banned in Chromium (see
http://chromium-cpp.appspot.com/)

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

+  static constexpr int FREQUENCY_50HZ = 50;
+  static constexpr int FREQUENCY_60HZ = 60;
+  static constexpr int FREQUENCY_MAX = FREQUENCY_60HZ;
+
+  // Functions
+  PowerLineFrequency(int freq);

[wolenetz, 2015/09/09 19:39:15]

use "explicit"

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

+  PowerLineFrequency& operator = (int freq);

[wolenetz, 2015/09/09 19:39:15]

For this and the next line, use consistent and correct whitespace.

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

+  PowerLineFrequency& operator =(const PowerLineFrequency& rhs);
+
+  // Automatically cast to int
+  operator int() const;
 };
 // Assert that the int:frequency mapping is correct.
 static_assert(static_cast<int>(PowerLineFrequency::FREQUENCY_DEFAULT) == 0,

[ajose, 2015/09/10 17:24:55]

Remove static_casts?

[suvanjanmukherjee, 2015/09/13 15:33:46]

Done.

               "static_cast<int>(FREQUENCY_DEFAULT) must equal 0.");
 static_assert(static_cast<int>(PowerLineFrequency::FREQUENCY_50HZ) == 50,
               "static_cast<int>(FREQUENCY_DEFAULT) must equal 50.");
 static_assert(static_cast<int>(PowerLineFrequency::FREQUENCY_60HZ) == 60,
               "static_cast<int>(FREQUENCY_DEFAULT) must equal 60.");
 
 // Some drivers use rational time per frame instead of float frame rate, this
 // constant k is used to convert between both: A fps -> [k/k*A] seconds/frame.
 const int kFrameRatePrecision = 10000;
 
@@ skipping 60 matching lines @@
   // Policy for resolution change.
   ResolutionChangePolicy resolution_change_policy;
 
   // User-specified power line frequency.
   PowerLineFrequency power_line_frequency;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_