Support ARIB STD B67, aka hybrid-log gamma (HLG) transfer function.

ui/gfx/color_space.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 UI_GFX_COLOR_SPACE_H_
 #define UI_GFX_COLOR_SPACE_H_
 
 #include <stdint.h>
 
 #include "base/gtest_prod_util.h"
@@ skipping 52 matching lines @@
     LINEAR = 8,
     LOG = 9,
     LOG_SQRT = 10,
     IEC61966_2_4 = 11,
     BT1361_ECG = 12,
     IEC61966_2_1 = 13,
     BT2020_10 = 14,
     BT2020_12 = 15,
     SMPTEST2084 = 16,
     SMPTEST428_1 = 17,
+    ARIB_STD_B67 = 18,  // AKA hybrid-log gamma, HLG.
 
     // Chrome-specific values start at 1000.
     GAMMA24 = 1000,
 
     // This is an ad-hoc transfer function that decodes SMPTE 2084 content
     // into a 0-1 range more or less suitable for viewing on a non-hdr
     // display.
     SMPTEST2084_NON_HDR,
 
     // TODO(hubbe): Need to store an approximation of the gamma function(s).
@@ skipping 64 matching lines @@
 
   friend class ICCProfile;
   friend class ColorSpaceToColorSpaceTransform;
   friend struct IPC::ParamTraits<gfx::ColorSpace>;
   FRIEND_TEST_ALL_PREFIXES(SimpleColorSpace, GetColorSpace);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_COLOR_SPACE_H_